ENGINEERING company Cleveland Bridge will have to rethink the lifting of the iconic arch feature of the new Wembley Stadium after defects were found in the steel.

But the North-East firm has pledged that any delays will not stop the stadium being completed on time.

Cleveland Bridge has pushed back technical boundaries to create the 440ft high arch, which represents the final section of the £757m sporting venue.

But reports yesterday suggested that computer checks had identified a string of weak spots caused by welding faults, as well as weaknesses in the concrete foundations.

Excavation crews were said to be burrowing into the foundations to check for air pockets.

However, project officials hit back yesterday by insisting that, although the arch was not yet ready to go up, it was not unsafe.

The Darlington company won a £60m contract to help create the London arena in September 2002, and was given responsibility for the 315-metre long arch.

Project bosses said that some minor rectification works were being carried out and pledged that the showpiece arch would be lifted into place later in the spring, still ahead of schedule.

Main contractor for the Wembley project, Multiplex Construction UK, said the arch was not unsafe but that "quality assurance checks" revealed more work was needed on the complex structure's 2,000 tonnes of steel.

It is believed that more welding work will be done on the massive structure before it is raised into position.

When the lifting does begin, it will take about two months for the arch to be put in place as it can only be moved five degrees at a time.

Ashley Muldoon, project director for Multiplex, said: "Extensive quality assurance checks are carried out on-site on a regular basis. These are procedural and, on occasion, some rectification work is required."

The stadium remains on target to open in 2006, with that year's FA Cup Final planned to be the first football match played there.

It will have the capacity to seat up to 90,000 spectators.