A Canadian family received an apology and a flight upgrade from British Airways, after suffering bed bug bites on a flight from Vancouver to London in early October.

The family consisting Ms Heather Szilagyi, her seven-year-old daughter Molly and her fiance Mr Eric Neilson, from British Columbia, Canada's westernmost province, were on the overnight flight when the bed bugs struck, reported CTV News.

Ms Szilagyi first noticed the bugs crawling out from behind the TV monitor in front of her. She wanted to catch them but they escaped, she told CTV News on Wednesday (Oct 18).

She saw more bugs later on through the flight, including during meal times.

When she discreetly informed a flight attendant, the attendant apologised but did not seem surprised, according to Ms Szilagyi.

"She was like, 'Oh ok, sorry about that. We're sold out. We don't have anywhere to move you'."

Ms Szilagyi told CTV News: "It was nine hours of knowing that I was probably going to get bitten, but not being sure."

When they arrived at their destination the following day, she and her daughter realised they were "absolutely covered" in bite marks.

Ms Szilagyi said she tried contacting the airline immediately to ensure they were not on the same plane on the return flight. However, she could not get through to a customer service agent, and her calls were answered by a recorded message saying the line was too busy and her call was dropped.

She eventually took photos of the bites and and posted them on microblogging site Twitter, with the hashtag #britishairways.

According to CTV News, Ms Szilagyi and her family heard from an airline representative a few days later, and were upgraded to business class for their return flight.

A British Airways spokesman said: "We have been in touch with our customer to apologise and investigate further.

"British Airways operates more than 280,000 flights every year, and reports of bed bugs onboard are extremely rare. Nevertheless, we are vigilant and continually monitor our aircraft."