Kashechewan First Nation in northern Ontario has begun evacuating residents after a water and sewage system failures left the fly-in community without safe drinking water and forced the nursing clinic to relocate.

More than 700 people have been evacuated so far while residents remain in the community waiting for flights.

A local state of emergency was declared earlier this month after the community's water treatment and wastewater plants were described as being in disrepair.

A 'do not consume water' order was issued on January 4.

The community has described the situation as a public health crisis, with sewage backing up into homes and contaminating the freshwater system.

Kashechewan First Nation's executive director, Tyson Wesley, said the pace of flights has been a source of frustration.

"Flights are kind of still at the same rate, even though we've asked to expedite the evacuation," he said.

A gastrointestinal outbreak has also been affecting residents, with Mr Wesley saying the community does not have the equipment needed to test stool samples and determine the cause.

He said he could not confirm whether people were ill due to a viral infection or after consuming tap water before the state of emergency was declared.

"We are worried about our community," Mr Wesley said.

The community's nursing clinic was evacuated on January 7 due to a sewage backup, with staff, patients and equipment moved to a nearby elementary school.

The facility is operating at about 40 per cent capacity and staff do not have access to diagnostic tools at the temporary location.

Kashechewan Chief Mr Hosea Wesley previously told APTN News the evacuation plan initially focused on residents with medical conditions, but expanded after sewage reached the clinic.

"When the clinic got flooded with sewer that's when everything changes," he said.

"Now we have to evacuate the whole community because the medical services are breached with sewer and back up in the clinic.

"You can smell the sewer as we speak right now. It's really not good for people to go in. It's a health and safety issue right now."

Evacuation flights initially took residents to Timmins and Kapuskasing in northern Ontario, before later transfers to Kingston, Ontario.

Around 200 evacuees are expected to stay in Kingston, while the next phase is expected to move about 1,700 people to Niagara Falls, Ontario, where more hotel rooms are available.

Loomex Group president and chief executive, Trent Gervais, said planning for evacuations typically begins with an assumption that people may need to stay away for at least 60 days.

"If it's two weeks, that's awesome. But there's so much planning to go into this that we start with 60 days and then after two or three weeks we're constantly re-evaluating to see if we need to extend," he said.

A spokesperson for Indigenous Services Canada, Eric Head, told CBC News water testing is underway and repairs are being completed at the water treatment plant.

Northern Waterworks has been deployed to install replacement pumps and bring additional equipment to complete the repair work.

Chief Hosea Wesley said in a statement the evacuation is not moving fast enough.

Kashechewan has faced water infrastructure problems for more than 30 years and there remains no timeline for when the water treatment system will be fully operational.