The closure of two major road tunnels for six weeks next summer will add to Birmingham’s traffic congestion problems, business leaders have warned.

Birmingham Chamber of Commerce estimates congestion in the city costs £2.3 billion per year in fuel and wasted time.

Birmingham city council has approved the closure of the A38 Queensway tunnels for repairs and new lighting, planned to coincide with school holidays, when the council has said traffic flows are 30 per cent lighter.

It said working on the tunnels during the day, rather than the night, was cheaper and the closure scheme was part of a package of measures aimed at saving about £14 million from the highways budget.

The tunnels, which are 40 years old, are the main through route for the A38.

John Lamb, spokesman for Birmingham Chamber of Commerce, said: “It’s going to cause a lot of trouble for people trying to get in and out of the city and for goods to get in and out of the city.

“And with the rail problems we’re having at the moment it’s not going to help.

“It’s clearly essential work and shows the frailties of Birmingham’s road system. It’s going to add to the problems.”

There have been ongoing problems on London Midland train services due to driver shortages.

London Midland has repeatedly apologised for the problem, which is expected to be resolved by mid-December.

The council said alternative routes would be promoted during the refurbishment, which will begin in July, and signs would be put in place to divert traffic via St Chad’s Circus, Great Charles Street, Paradise Circus and Suffolk Street.

Katie Teasdale, director of policy and strategic relationships at the chamber of commerce, said: “The closure of the Queensway tunnels will clearly have an impact on accessibility to the city and will add to Birmingham’s congestion issues which currently amount to £2 billion every year.

“It is vital that the Highways Agency and Birmingham City Council work hard to improve awareness and promote alternative routes into the city centre including public transport.

“Let us hope that the train cancellation problems end soon.”