A controversial city bypass will be completed ahead of schedule, ministers have pledged, as they said the £745 million project is closer to starting.

Work on the Aberdeen Western Peripheral Route had been held up by a legal challenge and the project was due to be completed in spring of 2018. But Infrastructure, Investment and Cities Secretary Keith Brown announced it would be finished in the winter of 2017.

The claim comes after a letter confirming the intention to award the contract to Connect Roads was issued, with Transport Scotland saying the process is in its final phase. The road will carry traffic 28 miles around the city. The project includes a second road from Stonehaven in the south and the dualling of the A90 between Balmedie and Tipperty in the north.

Mr Brown said the progress of the Aberdeen Western Peripheral Route/Balmedie-Tipperty (AWPR/B-T) was "unprecedented". He added: "Since overcoming all the legal challenges back in October 2012, we have done all we can to accelerate the procurement and construction of the AWPR/B-T.

"Following the shortest procurement processes for a contract of this size and complexity - it has been just 23 months since the contract was put to the market - we have now been able to also bring the completion date forward to winter 2017."

Mr Brown said the project would boost the north-east economy by some £6 billion and create about 14,000 jobs over the next 30 years - including more than 1,000 jobs for the construction industry.

Businesses and drivers will see tangible benefits as a result of the faster journey times and reduced congestion, he added.

Mr Brown added: "More widely, we are committed to making improvements at the Haudagain roundabout once work on the AWPR scheme is finished and are reviewing the programme in the light of the new completion date.

"We are investing in a new Inveramsay bridge on the A96, have made a longer-term commitment to dual the A96 between Aberdeen and Inverness and are investing £170m to improve rail links between the two cities.

"We have committed nearly £1bn towards improving transport infrastructure in the north-east, which shows without question the Scottish Government's determination to improve transport infrastructure in the north-east, and I look forward to road users feeling the benefits of the scheme being realised earlier."

The Scottish Government is to pay more than 80 per cent of the cost of building the new road, with Aberdeen City Council and Aberdeenshire Council contributing £75m each.

Aberdeen City Council leader Jenny Laing said: "I am delighted to hear we have reached this very important stage in the tender process.

"I am sure the people in the north-east will be delighted to learn this hugely significant project is progressing and we are another step closer to the delivery of the much-needed AWPR."

Jim Gifford, leader of Aberdeenshire Council, said: "It is very satisfying to reach this stage of the tender process.

"With preparatory work already under way on some sections of the route, we'll soon be able to see this important infrastructure project taking shape."