Super League teams could play a round of matches at Cardiff's Millennium Stadium next season.
A secret plan, which has been discussed by clubs, would see all six fixtures on one weekend staged in the city, three on the Saturday and three on Sunday.
If the proposal is agreed, Super League 2007 will be reduced by one round.
Each club will play 13 home and 13 away fixtures plus the game 'on the road', freeing up a weekend for a mid-season Test match.
The Welsh Tourist Board and Cardiff Council are both understood to be willing to offer a cash incentive of up to £500,000 to persuade clubs to back the move.
A Rugby Football League spokesman said: "Super League is a tremendously successful competition and we are always looking for opportunities to showcase this.
"We are not in a position to confirm anything at this stage but we hope to make an announcement in the near future."
Super League staged a series of on-the-road fixtures in 1998, including ones in Swansea and Cardiff, but this will be the first time an entire round has been staged at one venue.
The proposal follows the success of the 2003, 2004 and 2005 Powergen Challenge Cup finals, which all attracted full houses to the Millennium Stadium.
The move would be seen as testing the water for a possible new Welsh Super League franchise in 2009.