A computer failure has left passengers stranded across the US after the glitch drastically disrupted the operations of US carrier United Airlines, the airline said.

"At approximately 7:15 pm central time (0015 GMT Saturday), United Airlines experienced a computer outage interrupting the airline's flight departures, airport processing and reservations systems," said the airline in a statement.

The problems have left thousands of passengers across the country stranded, some on planes and others waiting in airports.

"Our technology team is working to resolve the issue as soon as possible," said the statement. The Chicago-based airline did not confirm how many airlines were effected by the outage.

"We apologize for the disruption being caused to travelers at affected airports and we are seeking to resume operations as quickly as possible."

One airline traveler in Portland, quoted by the Denver Post, said the airline had announced to passengers they were "having systemwide computer problems affecting everything from reservations to weather reports for pilots," and that the failures meant "all planes worldwide were grounded."

United merged with Continental on October 1 last year to form the world's largest airline group, with a cumulative total of some 5,820 flights daily, though both companies still exist separately.