Cardiff can do Newport a good turn by defeating Llanelli at the Arms Park on Friday and leaving Newport with a title chance if they in turn beat Bridgend on Saturday.
If Cardiff win and Newport lose, it would be Cardiff's title, but if Llanelli win on Friday, they will be the champions.
The three clubs, plus current leaders Neath, have already secured places in next season's Heineken Cup, with the fifth place going to Swansea or Pontypridd - the latter gaining the place if they defeat Sale Sharks and win the Parker Pen Shield on May 26 at Oxford.
The current Welsh/Scottish League table for the top seven clubs is: -
RGC 1404 have celebrated their crowning as Division One East winners, after just one season of competitive rugby. A big crowd turned out to support the clubs 'Celebration Saturday' when they were presented with the SWALEC trophy following their definitive 45-0 home win against Rhydydfelin on 18 May.
A special video package as Pontypridd claimed the double for the first time in their history by winning the Principality Premiership final, including match build-up, highlights, post match reaction and dressing room celebrations.