UPDATED 7.00pm: Eight children, aged between 18 months and 15 years, have been found dead in a house in Cairns, with a woman believed to be their mother in hospital with stab wounds.

Emergency crews were called to a home on Murray Street in the Cairns suburb of Manoora, around 11.30am (AEDT) on Friday.

A 34-year-old woman has been taken to hospital and is assisting with police inquiries but is not under arrest.

The woman's cousin, Lisa Thaiday, told AAP at the scene the children were all siblings and the woman was their mother.

Ms Thaiday said another sibling, a 20-year-old man, arrived home to find his brothers and sisters dead inside the house.

He is now being comforted by other family members.

"I'm going to see him now, he needs comforting," Ms Thaiday said.

She described the family and extended relatives as close-knit.

"We're a big family and most of us are from the (Torres) Strait," she said.

"I just can't believe it. We just found out, those poor babies."

Cairns Regional Crime Co-ordinator Detective Inspector Bruno Asnicar could not rule out the number of deaths may rise.

The street has been cordoned off and a crime scene will remain in place for at least the next day, Det Insp Asnicar told reporters at the scene.

It was an "extremely distressing" scene for the first response officers, he said.

Specialist police officers were travelling from Brisbane to assist with the investigation, Det Insp Asnicar said.

"We are missing nothing as far as conducting this investigation," he said.

"This is not a small job, we're not taking this lightly at all ... we'll cover every angle before this is finished."

The incident was a tragic event, but there was no need for the public to be concerned about their safety, he said.

About 20 to 30 people, including neighbours and locals, could be seen to be visibly upset and comforting each other at the scene.

Prime Minister Tony Abbott and Queensland Premier Campbell Newman have released statements, expressing their shock and sadness at the incident.

"Tonight, there will be tears and prayers across our country for these children," Mr Abbott said in a statement.

"All parents would feel a gut-wrenching sadness at what has happened."

Mr Abbott said these were trying days for a country still reeling from the deaths of two hostages after the Sydney siege tragedy.

Sky's Georgina McKerrow says the suburb is about 10 minutes out of the CBD.

"There's dozens of police down there at the moment. They've actually blocked either end of Murray St, the street where this has happened off.

"So traffic and pedestrians have been blocked from either side of the street."

FULL STATEMENT

Cairns detectives have established a crime scene and begun an investigation into the death of eight children in Manoora this morning.

Police were called to the Murray Street residence around 11.20am following reports of a woman with serious injuries.

During an examination of the residence police located the bodies of the children, all aged between 18 months and 15 years.

The woman, believed to be aged in her 30s, is receiving treatment for her injuries and is currently assisting police with their investigations.

A Mobile Police Facility has been established and officers from the Cairns Criminal Investigation Branch, Child Protection and Investigation Unit, Scenes of Crime and Scientific section are conducting an investigation and examination of the scene.

The road is currently closed and no further information is available at this stage.