Cezary Bednarski of London-based Studio E Architects enlisted Lord Rogers' aid after plans were announced to scrap the £1.8m Hadrian Bridge, which he won a competition to design in 1997.
Bednarski said Lord Rogers was to write to the Millennium Commission, Carlisle council and culture secretary Chris Smith to argue the case for the bridge.
The council has asked the Millennium Commission to reconsider funding the project and a decision on its future is due to this month.
Bednarski said the project, part of Carlisle's £11m millennium construction programme, had been hampered by local politics.
He said: "We could start in four weeks but the council is trying to cancel this project to fund other projects.
"We don't want to embarrass the council – just get it to change its mind. This bridge is really special." Bednarski said the footbridge could be built for £1.8m, but the council believed that it would cost more than £2m, and wants to terminate the project so that it can reallocate the money to millennium projects that are facing cost overruns that will not be met by the commission.
Studio E designed the stress-ribbon bridge in 1997, when the estimated cost was put at £700 000.
The bridge will be 180 m long and 3.9 m wide, with pedestrian and cycle paths.
The bridge is part of Carlisle's gateway city project, which also includes a gallery with a glass pyramid and glass cube. All of these projects have been hit by rising costs.
Controversy surrounding the bridge erupted last year when Carlisle council told contractors that the bridge had to be built for £1.49m or it would be scrapped.
The Millennium Commission confirmed that it was meeting on 14 February to discuss the project.
Carlisle council was unavailable for comment.