Friends have described Mia Ayliffe-Chung as an infectiously happy young woman as news of her death in Home Hill, a rural town about 75km south-east of Townsville, spreads to her former home on the Gold Coast.

The 21-year-old arrived in Australia about a year ago on a working holiday. She had been working as a waitress at Gold Coast nightclubs before making her way north for the backpacker rite of passage on the harvest trail.

She completed her first day on a sugarcane farm on August 17 and began sharing photos of her experience on social media.

A spokeswoman for British High Commissioner Menna Rawlings, who had flown to Townsville, said support was being made available to Miss Ayliffe-Chung's family as well as the family of another British national injured in the attack.

"We are working with local authorities and providing support to the families after one British national was killed and another critically injured in an incident in Australia," the spokeswoman said.

"Our thoughts are with the families at this difficult time. High Commission staff have deployed to Townsville and we remain in close contact with local authorities."

Federal police have been brought in to help investigate whether the fatal stabbing was linked to Islamic extremism after the alleged attacker reportedly used the phrase "Allahu Akbar".

Fairfax Media understands that the alleged attacker was not outwardly Muslim and, while police are still investigating possible links to extremism, as of Wednesday late afternoon there were no immediate signs he was an extremist beyond his cries of "Allahu Akbar".

Police were pursuing information including from counterparts in France about the man's mental health and possible drug use.

Sources also said there were no known significant hostilities between the alleged attacker and the victims before the stabbings.

Earlier, Queensland Police Service Deputy Commissioner Steve Gollschewski said he was not ruling out any motivations and police would also investigate whether drug or mental health issues played a role.

A local man, 46, suffered non-life-threatening injuries and a dog was fatally stabbed in a "terrible scene" at Home Hill Backpackers about 11.15pm on Tuesday.

A 29-year-old French national arrested at the scene was in police custody in Townsville Hospital on Wednesday. At this stage, no charges have been laid.

Deputy Commissioner Gollschewski said

police were not searching for anyone else in relation to the incident.

"There is no known ongoing threat to the community arising from this incident," he said.

"This is not about race or religion.

"It is individual criminal behaviour."

He stressed the incident was being treated as a homicide but said the Queensland Police Service would continue to work with its federal counterparts.

Consular officials have contacted the families of the British backpackers.

There were more than 30 witnesses to the incident, described by local officers as a "terrible" scene.

Mr Gollschewski said the British woman was believed to have been attacked first.

He said the Frenchman had been in Australia on a temporary visa since March but had not come in through Queensland initially.

The 29-year-old had no links to Islamic State, was not known to police and was not on any terrorism watch lists, Mr Gollschewski said.

Australian Federal Police Commander Sharon Cowden said there was nothing to indicate the man wasn't acting alone but said the community should remain vigilant after the "shocking" incident.

"This was a senseless act of violence and it's not tolerated in our society," she said.

"Through our international relationships, with international law enforcement, we are speaking with all the appropriate international law enforcement.

"We're working very closely with the Queensland police and will offer any assistance to this investigation."

Queensland Police Minister Bill Byrne said the events were tragic and disturbing.

"Right now our thoughts are with the victims' family and friends and the close knit community of Home Hill," he said, in a statement.

"I have been briefed by the Police Commissioner on the incident and I remain in contact with him as the investigation unfolds."

- with Nathanael Cooper and David Wroe