Manchester City are thought to be keen to reunite manager Mark Hughes with the Paraguayan, who had an impressive season last term, but Allardyce is adamant no offers had yet been forthcoming.
"There have been no bids whatsoever for Roque Santa Cruz," Allardyce said. "At the moment I'm more focused on getting him fit because I haven't seen him play since I've been here.
"I'm looking to getting him fit and producing the form that he produced last year to get us out of trouble. I'm also more focused on getting players in rather than players out.
"Certainly my focus over the last two days has been speaking to the chairman about that. We're both going to go out and try and improve our squad as quickly as possible."
Santa Cruz has made his intentions clear after claiming he would love to move on if an offer came in, but Allardyce also hit out at the transfer window, branding it "destructive".
He added: "Everybody knows that January is not positive. It's a very difficult window to work in. Generally the inflation that comes with a window as small as this is in many cases bordering on diabolical.
"But, if you don't pay the money, you don't get the player and that's why lots and lots of money changes hands at this particular period.
"It's destructive, it causes so many problems for players and managers, you just want to get it out of the way most of the time and get on with your job. Lots of speculation flies around that you can't control that can actually disrupt your squad and your preparation.
"I've never been a lover of this system. It's never really worked correctly and it never will but I don't think we'll ever get it changed."
However, the former Bolton and Newcastle boss admits he would utilise it as Rovers look to pull away from the relegation zone.
Allardyce has enjoyed a three-match unbeaten run since taking over at Ewood Park from Paul Ince but Rovers are still deep in trouble, lying next to bottom going into the New Year, and he is anxious to strengthen his squad.
"From our point of view, finding that player or two that would improve the squad immediately is important because it would lift us all.
"There are fewer and fewer bargains now than ever before and, if there are bargains, there are more clubs chasing them than ever before.
"It becomes quite difficult and I think targeting a player is probably a little easier than clinching it now, certainly if he is considered to be a bargain.
"We will try and get players than can make an impact on the team, otherwise I would prefer to go with the squad that I've got now, not lose anybody and make sure that we get out of trouble."