Merseytravel said it is too late to change routes

Neither "The Met" and "M Trams" consortia submitted bids to meet a deadline on Thursday, each asking for two more weeks.

Liverpool City Council has called for last-minute changes to proposed routes.

Merseytravel, which is masterminding the project, says the council must rethink its proposal.

This is a major scheme, which is going to put Liverpool and Merseyside in the forefront - it must not fail Louise Ellman

Problems began three weeks ago when the council proposed a new route based on a hybrid of the planned lines two, which ends at Whiston Hospital, and three that ends at Liverpool John Lennon Airport.

Instead part of the current line two would be replaced, and the proposed new route would then be diverted to the airport.

A Merseytravel spokesman told BBC News Online: "The bidders have been working for 12 months spending more than a million pounds each - it is too late to change."

He said Merseytravel stood by the original plans for the tram service, adding, "We just hope the council will reconsider."

A city council statement said: "Both Liverpool City Council and Merseytravel are committed to the Merseytram scheme."

It said the council was having continuing discussions about delivering the scheme on time and on budget, but did not explain the reasons why they wanted changes to the route.

Liverpool Riverside MP Louise Ellman said: "It is up to the city council to explain exactly what is going on.

"This is a major scheme, which is going to put Liverpool and Merseyside in the forefront - it must not fail."