About 270 pilot whales became stranded in three locations at Macquarie Harbour and Ocean Beach on Monday.

About 60 rescuers are hopeful tides and weather will work in their favour as they begin the rescue near Macquarie Heads for about 270 long finned pilot whales, in three locations.

Department of Primary Industry, Parks, Water and Environment marine conservation program wildlife biologist Dr Kris Carlyon is leading the rescue and says triage would be important in the first stage.

"We have animals spread over a large area, we will take those with the best chance. Some animals may be too big or in an unsuitable location," Dr Carlyon said.

"We will take some from the most accessible area, assess their behaviour and if we can refloat them. It will be a phased approach, we will assess what we are capable of and go from there."

Dr Carlyon said that late on Monday about one third of the estimated 270 whales had already died.

Marine Conservation Program staff assessed the condition of the whales on Monday afternoon and developed the approach forward.

PWS North-West Regional Manager Nic Deka said it was "difficult to assess how many might be dead".

"The main pod that have been stranded is on a sand bar about 100 metres off the Macquarie Heads boat ramp and there is another pod a further several hundred metres out from there," he said.

"They are in water but it is very difficult to see how many of those whales might be deceased or what condition they are in.

"Of the ones that are stranded just outside the heads on Ocean Beach there are about 30 whales there... and it appears about 25 of those whales have died."

Mr Deka said the incident was not unprecedented.

"Whale strandings are not uncommon in Tasmania and whale strandings of this scale are not uncommon either, but certainly we haven't had one for at least 10 years," he said.

"Strahan, Ocean Beach and Macquarie Harbor appears to be a hot spot for whatever reason. It may have something to do with their navigation and with false echos."

If required, volunteers will be used, but no members of the public will be called on.

"We have volunteers throughout the state and we will call on the volunteers if it is necessary and those volunteers have the confidence they can do the job safely, these are big animals so those that are untrained can be put at risk," Mr Deka said.

Vanessa Pirotta from the Macquarie University Marine Predator Research Group said the whales would be under a lot of stress.

"For any conservationist this is always a massive task, you're working toward a timeframe, whales risk overheating - they've never felt the weight of their bodies before, they could die under their own weight," she said.

"It is a very significant stranding even. It is making international news. People care about whales. They want to see a good resolution.

"I think it's highly unlikely all of them will be able to return - we might lose a couple."

Premier Peter Gutwein said he was thankful for the efforts from the DPIPWE, marine conservation experts and Tasmania Police

"I have made it very clear to those managing the effort that if additional resources are required, we will not hesitate to organise the support needed," he said.

"At times like these, Tasmanians work together to respond as quickly and compassionately, and my thoughts are with those assisting with the efforts."