Work is due to start on the new lanes later this year

The �32.2m scheme will involve adding the climbing lanes on four sections.

Roads Minister David Jamieson said: "It will significantly improve journey times on sections of the M4 and M5 for local and long-distance travellers."

A contractor has been employed and work is due to start later this year, said Mr Jamieson.

The work will take place at the M4 east at junction 18, the M5 north at Hallen Hill (between junction 18A and 17) and Tickenham Hill (between 20 and 19), and the M5 south at Naish Hill (between junction 19 and 20).

Mr Jamieson added: "These stretches of motorway are busy routes, and on the M5 in particular slow-moving traffic on the inside lanes causes delays, especially during holiday periods.

"These improvements will bring real benefits to motorists using these important roads."

Work is expected to start on the M4 eastbound diverge and M5 Hallen Hill later this year.

The other two M5 schemes will start during 2005.