The Black Cats are short of available forwards after the departures of Fraizer Campbell and Ji Dong-won, while Louis Saha had his contract terminated by mutual consent.
O'Neill is still trying to push through a deal to sign Danny Graham from Swansea, who provide Sunderland's opposition at the Stadium of Light on Tuesday.
When asked if strikers were his main priority, O'Neill said: "Of course, of course it is. I am hopeful that something will develop for us.
"We have got a couple of days left and we are hoping ourselves that we can add somebody else to the squad if at all possible.
"We are still looking there because come February 1, that's it. But we will see what we can do.
"There are some days left here and we will try to do something about it. I am hopeful, but there's nothing guaranteed.
"If we are left with this squad, then we would have to try to manage it as best we can, but I am still hoping we can do something."