Air Canada has apologised after kicking two passengers off a flight for refusing to sit in vomit-stained seats.

Susan Benson, who was on the Las Vegas-Montreal service, said the pilot warned the passengers they would be put on a no-fly list if they kept complaining.

She added that staff had tried to cover “a bit of a foul smell” with perfume and coffee grinds.

Air Canada said the passengers “clearly did not receive the standard of care to which they were entitled to”.

“We didn’t know at first what the problem was,” Ms Benson posted on Facebook of the flight late last month.

“Apparently, on the previous flight someone had vomited. The flight attendant was very apologetic but explained that the flight was full.”

She said staff “placed coffee grinds in the seat pouch and sprayed perfume”, but that the seat and seatbelt were “wet and there was still visible vomit residue”.

Ms Benson said the pilot came out of the cockpit after several minutes of “back-and-forth”.

The passengers were told “they could leave the plane… and organise flights on their own dime, or they would be escorted off by security and placed on a no-fly list!”

They were then escorted off by security.

Ms Benson said the row made her “ashamed to be a Canadian and ashamed of Air Canada”.

Air Canada said it was “reviewing this serious matter” and that “operating procedures were not followed correctly in this instance”.