SYDNEY, Dec 22 (Reuters) - The southern hemisphere’s three major rugby unions have signed a $323 million five-year contract with News Limited <NWS.N> and South Africa’s Supersport to secure the financial future of the expanded Tri-nations and Super 14.

After months of speculation, SANZAR, the governing body of the South African, New Zealand and Australian unions, announced on Wednesday it had agreed to extend the current 10-year deal, which expires at the end of 2005, through to 2010.

"This is a superb result for rugby as it allows us to plan the future with certainty and confidence," SANZAR and New Zealand Rugby Union (NZRU) chief executive Chris Moller said in a statement.

The new agreement covers broadcast rights for the three SANZAR countries and the United Kingdom, with News Limited acquiring the rights for New Zealand, Australia and Britain and Supersport securing the rights for Africa.

It does not include the broadcast market in France or other markets in Asia, the Americas or the rest of Europe.

SANZAR estimates additional rights could be worth $20-30 million, raising the value of the entire package to around $350 million.

"This broadcast agreement is a vote of confidence in the game’s future and contradicts the predictions of many commentators who said SANZAR would not receive as much for these rights as we did in the original agreement," South African Rugby chief executive Johan Prinsloo said.

SANZAR signed the original $555 million 10-year contract with News Ltd in Johannesburg on the day before the 1995 World Cup final, paving the way for the sport to turn professional.

Despite the growing popularity of rugby, there were concerns a new deal would come at a reduced price, but the final agreement represents an additional windfall of $12 million a year.

"In spite of talk of a depressed global sports rights market and the odd doomsayer, the new SANZAR broadcast agreement is well in excess of the original deal that has served rugby and its broadcasters so well," Australian Rugby Union chief executive Gary Flowers said.

As part of the new deal, SANZAR agreed to expand its two major competitions, the Tri-nations and Super 12, increasing the number of matches and broadcast content.

The Tri-nations will be increased from two to three rounds, taking the total number of test matches from six to nine.

And two new teams will be added to the expanded Super 14 provincial tournament, lifting the number of matches from 69 to 94.

"We are delighted that our tremendously successful partnership with rugby union will continue for the next five years," News Ltd chief executive John Hartigan said.