The Celtic League will adopt a more traditional format from next season after
representatives from Wales, Scotland and Ireland agreed to make changes.
Munster defeated Neath 37-17 in Cardiff last February
There will also be a new initiative with the launch of a knock-out cup competition played over four independent weekends.
The main competition will now change to a 12-team league instead of the previous two-pool format with the top four progressing to the knock-out stages.
The league will also feature home and away matches which will bring a more meaningful fixture list of 22 competitive matches for the three unions.
Welsh Rugby Union chief executive David Moffett believes the decision is a major breakthrough while the IRFU have fought for such a format since its inception.
"The accord we have agreed for the Celtic League to be played on a
proper home and away basis from next season is a huge step forward for the
tournament,'' said Moffett.
''From a Welsh perspective, the announcement that our five new regional teams
will be competing in a full and proper fixture list next season is great news.
"It means there will be top-class, professional club rugby being played
throughout the rugby World Cup, giving the teams greater continuity than in the
Philip Browne, Chief Executive of the IRFU echoed his Welsh counter-part's views.
"We are very pleased that the new structure of a home and away Celtic League has been agreed,'' said Browne.
I hope the new cup competition will prove to be attractive to broadcasters, sponsors and public
IRFU Chief Executive
''It now allows us to develop the competition to its full potential.
''The introduction of a knock-out Celtic Cup competition is a further fillip which I hope will prove to be attractive to broadcasters, sponsors and the rugby public."
Bill Watson, chief executive of the Scottish Rugby Union, was also delighted with the outcome.
sought for some time to see the Celtic League expanded into a season-long
"The restructuring of the game in Wales has enabled the Celtic countries to
achieve our objective in a hugely meaningful way.
"Our competition next season will deliver more meaningful games of rugby,
raising the intensity of every game played.''
The Celtic League was launched in the summer of 2001 with 15 teams (4 Irish, 2 Scottish and 9 Welsh) split into two pools.
This season, the tournament featured 16 teams, with the arrival of a third Scottish team, the Borders.
Leinster Lions defeated Munster 24-20 in the first Celtic League final at Lansdowne Road while this season Munster were 37-17 winners over Neath at the Millennium Stadium.
The teams competing in both competitions next season are:
Ireland: Munster, Connacht, Leinster Lions, Ulster.
Scotland: Borders, Edinburgh Rugby, Glasgow Rugby.
Wales: Bridgend/Pontypridd Region, Cardiff Region, Ebbw Vale/Newport Region, Llanelli Region and Neath/Swansea region.