The sister of a former Hamilton woman feared dead after a crocodile attack describes the situation as the family's worst nightmare.

Cindy Waldron is feared dead after a crocodile dragged her away while swimming at Thornton Beach in Northern Queensland.

Childhood friends Cindy Waldron, who is presumed dead after a crocodile attack, and Leeann Mitchell, who tried to save her. Photo: Facebook.

Her friend Leeann Mitchell tried to pull her away from the crocodile but was unsuccessful.

The two friends were celebrating Leeann completing her cancer treatment with a trip to Daintree National Park, near Cape Tribulation, just north of Cairns, when the attack happened on Sunday.

Cindy allegedly yelled "a croc's got me", and Leeann tried and failed to wrestle her friend free from its jaw.

She hasn't been seen since.

"They'd only been in the water for no more than a minute (before the attack)," says Senior Constable Russell Parker, according to The Australian.

Cindy's father, who is from Tauranga, and her sister have arrived in Northern Queensland and will stay there until the search is called off.

Father Pat Waldron and sister Anna-Lee Waldron Annett talked to media from the Daintree's Thornton beach.

Pat Waldron says his daughter would often do "crazy" things.

"What she did there is a crazy thing, absolutely. What a horrible way to end.

"She didn't deserve that."

It was an emotional visit to the beach to say goodbye after expressing gratitude for the massive search effort.

"We need to be here and cry on the beach," says Pat.

Anna-Lee Waldron Annett described the incident as a "nightmare" but also paid tribute those who have been carrying out the search.

"It's pretty overwhelming to know so many people care and have given up their time to help with the search. She was worth it.

"She was the most amazing person you will ever meet, kind, caring, generous to a fault."

The family have vowed to stay in the area until the search is called off.

Police confirmed it has now become a recovery mission.

While bad weather delayed State Emergency Service crews searching early on Wednesday morning, they laid wreaths at the beach as a mark of respect for Cindy.

The search is now focused on Cooper Creek, where five crocodile traps have been laid.

Specialist searchers have arrived on the scene.

- Stuff