Wales star Sam Warburton insisted Thursday he was only prepared to sign a central contract with the Welsh Rugby Union (WRU) if it meant he could continue to play for Cardiff Blues.

Last week regular Wales captain Warburton became the first player to sign one of the controversial new central contracts, designed by the WRU to stop Welsh players leaving the four professional regional teams for wealthier clubs in France and England.

However, the regions are in dispute with the WRU over the future of the club game in Wales and have stated that, as yet, no agreement exists to field centrally-contracted players.

This risks leaving Warburton in 'limbo' but the back-row forward, in a column for Thursday's Daily Telegraph, said: "I told the union I only wanted to sign a central contract if I could play for the Cardiff Blues.

"I hope nobody thinks that I am turning my back on the Blues, added Warburton, set to be on the bench for defending champions Wales' Six Nations opener against Italy in Cardiff on Saturday following a shoulder injury.

Warburton's decision bucks a recent trend that has seen several of his Test team-mates already opt for club careers outside of Wales, with full-back Leigh Halfpenny set to join them next season after agreeing to move to French giants Toulon, the reigning European champions.

But Alun Wyn Jones, who will captain Wales this weekend after also taking over the leadership of the British and Irish Lions for their decisive third Test win in Australia last year when tour skipper Warburton was injured, recently signed a new deal with Swansea-based region the Ospreys.

The situation in Wales has been complicated by the ongoing uncertainty concerning the fate of next season's European Cup, with the regions supportive of an English Premiership plan to launch a rival Rugby Champions Cup.

Warburton, 25, is understood to have been one of just six players coming to the end of regional deals who were offered a central contract by the WRU.

In a statement on Thursday, the WRU tried to present central contracts as an 'insurance policy,' amid rumours they might loan players to Premiership clubs.

"The clear intention is to ensure the four regions have the opportunity of gathering the strongest squads possible to compete on domestic and European stages," the WRU said.

In pursuit of that objective, the governing body said it had "encouraged" the Scarlets to "conclude negotiations" with Rhys Priestland and Scott Williams, and the Ospreys to do likewise with Adam Jones.

On Wednesday, umbrella group Regional Rugby Wales declared its "utmost respect" for Warburton but queried how WRU contracts could work in Wales as things stood.

"The regions would question how one national contract works as a constructive and sustainable strategy for the whole of Welsh rugby given that we have some 200 professional players in Wales contracted to the regions."

But Warburton, who had been linked with a move to Toulon, said a central contract system could succeed in Wales, just as it had in Ireland where the bulk of Test stars are on provincial deals bankrolled by the Irish Rugby Football Union.

"I am sure more Wales players will sign up, and it will become clear that it is not the WRU competing against the regions. It is about everyone working together."