Detectives investigating the deaths of eight children in Cairns are considering the possibility the prime suspect – the mother of seven of the children – was on the drug ice at the time of the deaths.

Mersane Warria, 37, remained under police guard in Cairns Hospital with knife wounds on Sunday morning.

She has been formally interviewed as part of the investigation.

Detetive Inspector Bruno Asnicar said he would not comment on the speculation, other than to say it was an element of the police investigation.

"These are all things that will be presented to a court," he said.

"As you can imagine, all of these things are extremely relevant and I understand that people are very interested in those facts."

But Inspector Asnicar did say it was a "very important part of the investigation".

In another development overnight, it emerged not all the children had been stabbed to death.

"We won't get that [information] until after the post mortems," he said.

"…It could be a range of things, from suffocation to a thousand other things, that might have been the cause of death."

He said the post mortems would likely be completed by Sunday afternoon at the earliest.

It is understood charges could be laid shortly after that forensic investigation.

About 100 people had been interviewed as part of the investigation, he said.

"When you're dealing with murder, there's nothing that's done half-way," he said.

"It's very intense and everything's collated very accurately."

Acting Assistant Commissioner Paul Taylor said it was disappointing to see some media naming and showing images of the dead children in defiance of indigenous cultural protocols.

Mr Taylor said the community had been "disappointed" with the decision to publish.

"There's been a number of photos and names shown, which to a degree is disappointing in some of the newspapers, particularly down south," he said.

"Clearly they haven't come from the police.

"We understand and respect the role of the media, but our relationship with the community is paramount and we've taken steps today to reassure them that that information hasn't come from us."

Several church services on Sunday will remember the children - four girls aged two, 11, 12 and 14 and four boys aged five, six, eight and nine. Ms Warria was the mother of the seven youngest children and the eldest girl's aunt.