Italian Prime Minister Romano Prodi Tuesday gave his support to the Brenner tunnel project, aiming to battle an explosion of Alpine traffic, at a meeting with Austrian Chancellor Wolfgang Schuessel.

"The Brenner is an absolute priority for Italy, it is vital for Italy," Prodi said at a joint news conference.

"We both agree that the Brenner tunnel is the most fascinating (transport) project of the EU," Schuessel said, announcing the start of initial studies for the massive building site on June 30, the last day of the Austrian presidency of the European Union.

The Austrian government has been trying to reduce increasing traffic on the main north-south Brenner Pass through the Alps ever since the EU ended quotas set up by the Austrian government to reduce the number of heavy trucks there.

Austria hopes to relieve the congestion by building the 52 kilometre (30 mile) long rail tunnel in the same area, on the Italo-Austrian border. Construction is set to start in 2008.

Up to 20 percent of the estimated cost of seven to eight billion euros (8.8 to 10 billion dollars) is due to be financed by the EU, but the Austrian social democrat opposition and some business groups are opposed to the plan due to its cost.

In 2004, heavy truck traffic over the Brenner rose to more than two million vehicles compared to 900,000 in 1991.

At the end of May, some 2,000 environmentalists blocked the Brenner Pass in protest against heavy road traffic and growing pollution.

Prodi, recently criticised by Vienna for hesitating over the issue, on Tuesday underlined Rome's full support for the Alpine Convention, which aims to guarantee the protection of the region and has been signed by eight countries, including Italy.

"I say yes now to the Alpine convention. Italy is on board now. We have a responsibility to be custodians of the Alps," he said.