Western Australia's iconic Carnaby's cockatoo could be lost from the Perth metropolitan area if pine plantation clearing in the city's north is not halted, WWF Australia has warned.

There has been a 53 per cent decline since 2010 in the northern population, which feeds and roosts in the Gnangara-Yanchep-Pinjar pine plantation, according to figures from Birdlife Australia.

Carnaby's cockatoos adapted to pine as a food source after the decline of the now-endangered Banksia woodlands.

WWF Australia species conservation manager Merril Halley said the WA Government's decision to stop replanting the 23,000 hectare pine plantation in the early 2000s was now posing a threat to the species.

"Since 2004, there's been no real replanting occurring, and [the area] is down to about 8,500 hectares of the pine plantation remaining," she said.

"That is a significant loss of that food source for the birds when they first come back to the coastal plane."

Google Earth image shows clearing in the Gnangara pines between 2002 and 2016. ( Supplied: Google Maps )

Ms Halley said government projections predicted a further halving of the bird's remaining population should the pine plantation be completely harvested.

"The modelling shows there will be a loss of 50 per cent of the birds over a number of years," she said.

"That's on top of the decline we're already seeing."

We are tackling decline: Minister

The State Government acknowledged the decline of the cockatoo population, and said it was working on a strategy to aid numbers while fulfilling contractual obligations and preparing for a bigger human population.

"The draft Strategic Assessment of the Perth and Peel regions has a specific aim of arresting the long term decline of the Carnaby's cockatoo," Environment Minister Albert Jacob said.

"Under business as usual, the Carnaby's cockatoo will continue to decline.

"The landscape scale response of the strategic assessment is the best option to protect this species."

The draft contains several measures to protect the species, including the creation of 700 artificial hollows between Eneabba and Ravensthorpe and a commitment to replant 5,000 hectares of pines to compensate for harvesting of the plantations.

The WA Government's plan does not protect the cockatoos at all, conservationists say. ( Supplied: Steven Castan )

Ms Halley said the WWF welcomed the concept of a strategic assessment, but said the plan did not go far enough.

"It does not protect Carnaby's cockatoos at all," she said.

"We're going to see the impact of implementing that plan will be huge loss and potentially the loss of the Carnaby's cockatoos from the Swan Coastal Plain."

Pine harvest must be stopped: WWF

Ms Halley said the clearing of the pine plantations needed to be halted until the habitat loss had been addressed, and urged Federal Environment Minister Josh Frydenburg to intervene.

"The continuing harvest of the pines must be stopped until there is agreement on how to properly address habitat loss for Carnaby's cockatoos," she said.

In 2002, the state entered a contract with Wesbeam for the supply of timber from softwood plantations around the Gnangara Mound, in an effort to protect the valuable underground water supply.

The Gnangara Mound — which is located under the plantations — provides approximately 30 per cent of Perth's drinking water each year.

"Retaining large areas of pine plantations within Gnangara, Pinjar and Yanchep ... would reduce ground water recharge into the Gnangara mound," Mr Jacob said.

Mr Jacob said the state was continuing to work with the Commonwealth to finalise the draft strategic assessment in 2017.