"It is tragic, it is sad ... there are police who have been traumatised by what has happened. It is our job, but it's never easy," Detective Chief Inspector Brendon Cullen.

The baby's body is believed to have drifted about 30 kilometres in the current for two days before washing ashore at Surfers Paradise beach, where she was found by passers-by about 12.30am on Monday.

Divers had been searching the Jack Evans Boat Harbour and Tweed River on Tuesday and Wednesday.

"We have NSW and Queensland police divers here examining waterways to see if there is any evidence ... of how the child got into the water," Inspector Cullen said.

The father's hearing to be extradited to NSW was delayed in Southport Magistrates Court on Wednesday because he faced other charges which had to be dealt with before the extradition could proceed.

Police sources in Queensland allege the mother admitted to knowing about the planned "sacrifice" - as it was described to AAP - but only the father would be accused of throwing her into the water.

It's believed the 23-year-old mother won't face charges and that she has been released from custody and placed in the mental health system in Queensland.

Detectives were continuing to appeal to anyone who may have seen the family-of-four in the Tweed Heads CBD, Broadbeach or Surfers Paradise area in the past week.

AAP