The Port of Southampton has expressed an interest in buying the local military docks at Marchwood after a boom in car traffic reduced expansion space at its own facilities to a single acre.

A surge in car handling at the 700-acre port has put space at a premium, forcing Southampton to build its fifth multi-deck storage facility-due to be opened next month by Stephen Hammond, the transport minister.

The need to build "upwards" is testament to the recovery in demand for new cars in both Britain and overseas, with Southampton seeing strong growth in car exports.

Such traffic at Southampton rose 72pc to 439,000 vehicles between 2009 and last year, when the port handled 31pc of UK car exports. Total car traffic at the port last year was 650,000 vehicles and port director Doug Morrison said: "This year, we'll probably do 750,000. Most of the growth is coming from exports, to the Far East in particular."

The port, which is owned by Associated British Ports, handles a range of car marques including Ford, Renault, BMW and Honda.

It is playing a major role in the growth of Jaguar Land Rover, whose impressive turnaround under Indian owner Tata Motors resulted in the car maker breaking the £1bn barrier for half-year profits earlier this month. Southampton handles around 60pc of JLR's UK exports.

Mr Morrison said: "Nothing I'm hearing makes me think the growth is going to stop." The port is forecasting a 30pc rise in car traffic over the next three years.

"We are the only port in the UK that's been forced to use multi-decks for new car business because the land isn't available," he said. "For obvious reasons we look very longingly at Marchwood."

The neighbouring 300-acre Marchwood Military Port, which employs around 150 civilians and 600 troops, was put under review by the Ministry of Defence as part of a cost-cutting plan.

Options included selling the facility and vacating it but the MoD has now decided to sell the site and lease it back. A tender for bidders is expected next year.

Mr Morrison said Southampton could use the facility, which has good rail connections, for its burgeoning car trade. The MoD could still handle its own traffic there, such as the recent return of almost 100 military vehicles from Afghanistan.

"If we acquired Marchwood, we would be able to create around 400 jobs,"Mr Morrison said."That would help offset some of the losses from the shipyard in Portsmouth," which BAE is closing. It would also allow some reorganisation of the port, whose plans to expand its container operations at Dibden Bay were blocked in 2004.