The 4.3-metre reptile was behaving differently to the crocs around it.

"We kept following it and locating it ... it had subtle behaviour differences that highlighted to us it was the target animal," Environment and Heritage Protection Conservation Operations Manager Chris Artiemie said.

"The behavioural tendencies we picked up were very subtle, but basking during the day - that usually means that it had had a rather large feed - and also just boldness, being out during the day."

On Monday the crocodile was trapped in the Mowbray River, south of Port Douglas and euthanised.

A post-mortem confirmed the the worst. Inside the animal were human remains, and some personal effects belonging to Ms Cameron.

More remains and Ms Cameron's walking stick were located last Thursday at Craiglie Creek, two days after she was last seen near an aged care facility.

Mr Artiemiew said he believed the animal was a recent arrival to the Craiglie water system and local wildlife officers did not recognise it.

Police say Ms Cameron's family have been notified and were coming to terms with the news.

"It's always difficult when we have a missing person who we suspect has been taken by a crocodile, there's always that personal element that touches every one of us," Inspector Edward Lukin told reporters.

A report is now being prepared for the coroner.

Ms Cameron's death has prompted Katter's Australian Party to renew calls for more stringent management of crocodiles, including culling.

Two other people - Warren Hughes, 35, and Cindy Waldron, 46 - have been killed by crocodiles in far north Queensland in the past 18 months.

Queensland Environment Minister Steven Miles said residents and visitors to far north Queensland must remain vigilant to the threat posed by crocodiles.

"We have permanent crocodile warning signs in place to remind people this is croc country. The signs are there to keep you safe so please acknowledge them," Mr Miles said.