Merthyr are the reigning Principality Welsh Premiership champions

The Welsh Rugby Union has confirmed the Principality Welsh Premiership will initially be divided into two groups of eight teams for the next two seasons.

The plans have already been approved by the clubs and been ratified by a WRU board.

Aberavon, Bridgend, Carmarthen Quins, Llandovery, Llanelli, Neath, RGC 1404 and Swansea will form the west.

Holders Merthyr, Bargoed, Bedwas, Cardiff, Cross Keys, Ebbw Vale, Newport and Pontypridd are in the east.

The clubs will play each other home and away in the first half of the season before all 16 sides join together, with points being carried over from the regional format.

The sides will then play each other once, meaning clubs will have 29 guaranteed league games.

At the split, points will be allocated to clubs based on league positions so the winners of the east and west leagues will go into the second half of the season with eight points.

The clubs in second place will carry seven points into the 16-team league, down to the eighth placed clubs who will carry one point.

There will be no end-of-season play-offs and the club who finishes top of the table will be crowned overall champions.

This format replaces last season's format when clubs were split into two sections of eight midway through the campaign based on positions in the table. There were only 22 guaranteed games for clubs in this competition.

Overall winners Merthyr won the Tier One final by defeating Aberavon, while Newport were the Tier Two winners after beating Neath.

Merthyr will launch the defence of their title at The Wern against Cross Keys when the new season kicks off on the weekend of 26 August.

Principality Premiership clubs will continue to work with the regions to select Regional Premiership Select XVs for the British & Irish Cup, while the Foster's Challenge Cup will not take place.

WRU head of rugby performance Geraint John said: "The Principality Premiership is a vital competition in underpinning the professional game in Wales, providing a crucial stepping stone for our potential future professional players, in addition to the British & Irish and Anglo-Welsh Cup competitions.

"We believe the new format and the additional, guaranteed local derbies in the first half of the season will further support the work of the regions to establish the place of the Principality Premiership within the regional and national pathway, in order to underpin player, coach and referee development. At this time we feel this solution meets the vast majority of those needs.

"We will continue to assess the outcomes of this new format but there will be no further structural changes to the Principality Premiership until at least the 2019/20 season."

Principality Premiership East: Bargoed, Bedwas, Cardiff, Cross Keys, Ebbw Vale, Merthyr, Newport, Pontypridd.

Principality Premiership West: Aberavon, Bridgend, Carmarthen Quins, Llandovery, Llanelli, Neath, RGC 1404, Swansea.