Dorset County Council recently voted for the scheme which is designed to ease congestion around Weymouth.

The 3.75km (2.3m) stretch of carriageway is aimed at tackling traffic jams along the A354 from Weymouth to Dorchester and the A353.

The Government Office for the South West confirmed it would not interfere in the local planning process.

Olympic Games

Angus Campbell, council leader, said: "This is fantastic news, and we are delighted the government has decided not to interfere.

"We can now get on with building the road, which has been badly needed for many years.

"And with the Olympic Games sailing events coming to Portland in 2012, it is more important than ever."

Compulsory purchase orders will now be made for the required land.

The council aims to start work on the road in January 2008, with the project due to be completed in 2011.

Protesters say the road will have an adverse impact on the environment.