POLICE boarded the anti-whaling ship Steve Irwin when it arrived in Hobart last night and confiscated the ship's log book and video footage.

The film depicts some of the most dramatic whale-killing scenes ever seen, crew on the Sea Shepherd Conservation Society ship told Hobart's Mercury.

Tasmanian crew member Andrew Perry said the video footage was harrowing because the Japanese whalers had become more brazen by the end of the hunting season and for the first time slaughtered a whale in full view of the Steve Irwin.

Mr Perry said the footage, taken from the ship's helicopter, showed a whaler's explosive-tipped harpoon piercing a whale. "The whale was then pulled alongside the (Japanese) boat and it was shot seven times with a shotgun."

He said the helicopter crew, filming for TV documentary show Animal Planet, then saw the whale thrashing and could hear it screaming.

Mr Perry said the slaughter took more than 20 minutes. "It was an incredibly distressing thing to behold," he said. "We have never been able to get footage like that before. It's going to be damning."

After violent clashes with Japanese whalers in the Southern Ocean, the Steve Irwin was met by Australian Federal Police when it docked in Hobart about 5.30pm. The police, who had search warrants, kept the crew on board as they searched cabins.

Steve Irwin captain Paul Watson said he was not told whether the police action stemmed from a complaint by the Australian Government or from the Japanese.

He said the Steve Irwin had never been searched before but he would welcome any charges that led to the crew facing a court. "My position is that if they want to put me on trial for anything connected with this, then I am happy to do it," Capt Watson said.

"We are not there protesting, we are down there to stop a blatantly criminal activity, to stop whaling in a whale sanctuary. These actions have to go to court somewhere, so let's start it here."

Capt Watson said the conservationists had risked their lives during the campaign and were willing to risk their freedom.

He said the campaign had ended four days earlier than intended because it was clear the Japanese whalers were "out of control". "They were frustrated, violent and attacking us," he said.

"I didn't want to get any of them killed or any of us killed."

The Australian Federal Police could not be contacted last night, though Tasmania Police confirmed federal officers met the ship.

The Steve Irwin was involved in its most extreme and dangerous clashes this season, culminating with the activist vessel crashing into the stern of the Yushin Maru 3 on February 7.

Capt Watson's crew said they were pelted with scrap metal, blasted with high-powered water canons and attacked with military-grade sonic weapons.

Mr Perry, of Hobart, said one of the reasons the Steve Irwin had concluded the campaign and returned to Hobart was because they had heard the Japanese had deployed a security vessel to track down the activists and seize the footage.

"We heard they had a commando boarding team whose objective was to find us and board us," he said.

He said the Sea Shepherd crew never intended to harm any of the whalers but simply to pester them and act as a deterrent.

`It's some of the most horrific footage ever - it had many of our crew in absolute tears.' Japanese whalers are getting more courageous, according to Tasmanian anti-whaling campaigner Andrew Perry who was on board the Steve Irwin's most recent anti-whaling campaign.

The Sea Shepherd Conservation Society's ship arrived in Hobart on Friday night only to have crucial footage of Japanese whaling operations in Australian and New Zealand waters near Antarctica seized by the Australian Federal Police.

"For the first time ever, whales were hunted and killed in front of the Sea Shepherd vessel," Mr Perry said.

"This was unexpected and distressing - normally just our presence would stop them from whaling, which is an effective win for us."

The crew were filming for Discovery Channel's documentary program Animal Planet.

"One piece of footage showed a whale being first harpooned with an explosive-tipped harpoon then dragged alongside the bow of the ship where a crew member then hung over the bow with a high-powered shot gun and shot this whale seven times to finally kill it.

"This whole process took over 25 minutes and during that time the whale was thrashing about and screaming in pain," Mr Perry said.

"It's some of the most horrific footage ever - it had many of our crew in absolute tears."

Mr Perry said the footage prompted the Japanese to petition the Australian Federal Police to seize the footage on the basis of criminal activities by Sea Shepherd crew.

"We haven't done anything criminal - what we're trying to do is prevent criminal activity ... I think they're extremely worried about the footage we've got," he said.

It is understood the Japanese ship deployed a security vessel with a commando boarding team to retrieve the footage.

Tasmanian Greens Senator Bob Brown yesterday demanded the Rudd Government explain the raid on the ship.

"If this action was taken at the behest of the Japanese authorities it will outrage many Australians," he said.

THE Federal Government has distanced itself from an Australian Federal Police (AFP) raid on the anti-whaling ship Steve Irwin made at the request of the Japanese.

Australian Greens leader Bob Brown is demanding the federal government explain why the AFP raided the Sea Shepherd vessel on Friday evening in Hobart.

But a spokeswoman for Home Affairs Minister Bob Debus said the matter was in the hands of the AFP.

"All we can say is that it's an operational matter and it would be inappropriate to comment,'' the spokeswoman told AAP.

"It's like any police investigation.''

After violent clashes with Japanese whalers in the Southern Ocean, the Steve Irwin was met by the AFP when it docked in Hobart early on Friday evening (AEDT) and officers confiscated the ship's log book and video footage.

The footage, taken by wildlife documentary group Animal Planet, depicted some of the most dramatic whale-killing scenes ever seen, crew on the Sea Shepherd Conservation Society ship said.

The police, who had search warrants, kept the crew on board as they searched cabins.

Senator Brown has written to Prime Minister Kevin Rudd calling for an immediate explanation as to how the raid could be in the nation's interest.

"On the face of it, this is outrageous behaviour by the Australian government to secure favour from the Japanese authorities,'' he said.

An AFP spokeswoman confirmed an investigation was launched at the request of the Japanese authorities, who this year complained after activists threw bottles of rancid butter at the whalers and tried to board a ship.

"I can confirm that a raid took place,'' an AFP spokeswoman said.

"An investigation was launched at the request of the Japanese authorities.''

Senator Brown said the raid would outrage many Australians.

"The Australian Federal Police can expect detailed questioning from the Greens at Senate Estimates this coming week,'' he said.

Senator Brown said he had been told by Steve Irwin captain Paul Watson that the ship was delayed coming into the port in Hobart so that the AFP had time to make their raid.

"I'm also told that the Japanese used absolutely outrageous tactics, like sound wave attacks on people in helicopters, which could have brought down those helicopters from the Sea Shepherd.''

Steve Irwin captain Paul Watson said the Steve Irwin had never been searched before but he would welcome any charges that led to the crew facing a court.

"My position is that if they want to put me on trial for anything connected with this, then I am happy to do it,'' Capt Watson said.

"We are not there protesting, we are down there to stop a blatantly criminal activity, to stop whaling in a whale sanctuary.

"These actions have to go to court somewhere, so let's start it here.''

Japan slaughters whales using a loophole in an international moratorium on commercial whaling that allows "lethal research'' on the mammals.