Sam Allardyce, the Blackburn Rovers, has urged Manchester City to make him an offer he can't refuse, as Mark Hughes continues to chase Roque Santa Cruz.

Hughes, the City manager, stepped up his interest in the player he brought to Ewood Park last season but his latest offer, believed to be worth £15million, was knocked back by his former club yesterday. The Welshman is desperate to strengthen his squad in the transfer window and is now considering whether to increase the offer for the Paraguay international.

"I can't second guess what Manchester City are going to do," Allardyce said. "Whatever happens between now and next week, as time goes on in this usual transfer window of mayhem, we will wait and see.

"You never say never about anything because you never know what is around the corner when January is on the boil. At the end there is always going to be a price, but there is no price we are going to put on Roque's head.

"It is down to Man City to make the offer and blow us out of the water. Obviously, we simply want him to play for us and help us stay in the Premier League, which is the most important thing for me and this club."

Allardyce has also been linked with a move for Sunderland striker El Hadji Diouf, a player he successfully managed during his time at Bolton. But Allardyce admits that move looks unlikely. "My information is he is not available," he added.