The crew had been working non-stop for the past 30 days to repair the almost 40-year-old vessel.

The conservation ship has been in dry dock at Launceston's Kings Wharf since last month.

Ship manager Pia Klemp said the boat was treated to a host of renovations.

"It got a brand-new prop, we did a lot of steel replacement along the hull - unfortunately we had a lot of damage from the ice, different weather conditions and sea conditions that we have to take our ships through," Ms Klemp said.

"We're very proud to say that the Steve Irwin is stronger, more efficient and faster than ever before, and now after all this work is completed, it is totally ready to take on the whale poachers down in Antarctica again."

The Steve Irwin set off with the high tide yesterday afternoon, bound for Williamstown, Melbourne, where it will berth alongside Sea Shepherd vessels the Sam Simon and the Bob Barker.

Ms Klemp said all three ships would now be preparing for the whaling season in Antarctica, which starts in December, and would be prepared to fight Japanese whaling ships if the situation arose.