BA boss refuses to resign as Heathrow endures third day of chaos

Passengers stand with their luggage outside Terminal 5 at London's Heathrow Airport after flights were cancelled at the weekend. Photo / AP

British Airways expects to run a full flight schedule at London's Heathrow tonight and tomorrow NZT after a worldwide computer system failure at the airline stranded tens of thousands of passengers, the airport says.

Heathrow was working with the airline to get delayed bags to passengers "as soon as possible", the airport said on Twitter.

"Our IT systems are now back up and running and we will be operating a full flight schedule at Heathrow and Gatwick," BA said on its website.

BA had been forced to cancel all its flights from Heathrow, Europe's busiest airport, and Gatwick at the weekend after a power supply problem disrupted its operations worldwide and also hit its call centres and website.

BA chief executive Alex Cruz has said he will not resign despite the disruption.

He has claimed the flight disruption had nothing to do with cutting costs, telling BBC News that a power surge, had "only lasted a few minutes", and that the back-up system had not worked properly.

He denied that the IT failure was due to technical staff being outsourced from the UK to India.

Cruz said he was "profusely sorry" to the thousands of passengers still stranded at airports worldwide and claimed around two thirds of passengers will have reached their destination by the end of today.

- additional reporting AAP