A legal challenge to Canada's new passenger bill of rights from a group of airlines is "ill-founded" and should be dismissed, according to the country's attorney general.

In a pair of court filings, lawyers for the federal government and the Canadian Transportation Agency (CTA) say the government will fight air carriers' attempt to overturn rules that beef up compensation for travellers subjected to delayed flights and damaged luggage.

In a motion to the Federal Court of Appeal earlier this month, Air Canada and Porter Airlines Inc. along with 15 other airlines and two industry groups argued the new regulations exceed the agency's authority and contravene the Montreal Convention, a multilateral treaty.

As of July 15, passengers can be compensated up to $2,400 if they are bumped from a flight and receive up to $2,100 for lost or damaged luggage. Compensation of up to $1,000 for delays and other payments for cancelled flights will take effect in December.

The issue came to the forefront after a 2017 incident in which two Montreal-bound Air Transat jets were diverted to Ottawa because of bad weather and held on the tarmac for up to six hours, leading some passengers to call 911 for rescue.

John McKenna, who heads the Air Transport Association of Canada — one of the applicants in the case — has called the new compensation grid "very high" and the new rules "outrageous," claiming they will trigger higher air fares.

Passenger-rights advocates say the rules do not go far enough, arguing the criteria for monetary compensation are tough to meet as passengers would have to present evidence that is typically in the hands of an airline.

The rules impose no obligation on airlines to pay customers for delays or cancellations if they were caused by mechanical problems discovered in a preflight check — walking around the aircraft before takeoff looking for defects — rather than during scheduled maintenance, which involves more thorough inspections required after 100 hours cumulatively in the air.

AirHelp, a Berlin-based passenger-rights company, has said the number of issues categorized as outside an airline's control amounts to a long list of ways to avoid compensating passengers.

Canada's transportation regulator says it will argue the appeal should be dismissed should the court choose to hear it.