Sam Tomkins has signed a two-year deal to promote a mouthguard in the United Kingdom but is giving no indication if he will be around long enough to fulfil all his obligations.

The 24-year-old Wigan and England fullback is widely expected to join the New Zealand Warriors in the NRL after the World Cup in November and has also been tipped to join older brother Joel in rugby unionip networking HK.

His presence at Joel's club Saracens for his unveiling as the brand ambassador for the mouthguard company did nothing to end the speculationphone cover cases.

Tomkins maintained a flat refusal to discuss his futurebeauty wigs.

"I'm concentrating on playing for Wigan. We've a tough game against Leeds this week and we've the play-offs coming up," he said.

"Then there's the World Cup in November so I've a lot to think about and I'm not looking beyond this year."

Tomkins was happy to talk about the prospects of Wigan completing a rare trophy double and the excitement building ahead of the World Cup.

He has played in just one of his club's last eight Super League matches going back to June, further fuelling rumours of a move, but defied injury to help Wigan lift the Challenge Cup last month, scoring the final try of the 16-0 win over Hull at Wembley.

"It's not often a Challenge Cup final comes around," he said.

"You don't know when the next one will be so, if you get a chance to play, you put your hand up."

Hugely influential for his club, Tomkins could also hold the key to England's hopes of winning the World Cup, which starts on October 26.