Sunderland manager O'Neill, relieved at the way his side came back to earn a 1-1 draw with north-east rivals Middlesbrough in a fourth round FA Cup derby tie, revealed he's still in the market for new recruits with the January 31 deadline for signings looming.
O'Neill failed with an initial bid for Davies, the veteran Bolton and former England forward, who is free to leave the Premier League strugglers after nine prolific seasons at the Reebok Stadium, where he is no longer guaranteed regular first-team football.
The 34-year-old striker is seen as an ideal short-term fix to bolster Sunderland's attacking options, which have been lessened by a broken nose suffered by Nicklas Bendtner that will keep the on-loan Arsenal forward out until March.
"I did make an inquiry about Kevin last week," O'Neill said after Sunday's fourth round tie.
"(Bolton manager) Owen Coyle wants to keep him, but won't stand in his way, so I may well follow that up.
"I'm mindful that come Wednesday morning, that's it as far as the squad I've got at my disposal for the rest of the season. We've got a couple of injuries to contend with, so we'll have a look at the situation. We might be unable to do something, but we've got a couple of days left to bolster the squad."
Meanwhile O'Neill welcomed the return of Fraizer Campbell, the former England Under-21 forward, who marked an end to a 17-month injury absence with a well-taken equaliser to earn a replay as the local rivals battle it out for the right to host Arsenal in the last 16.
After coming off the bench to help turn the tide, former Manchester United forward Campbell admitted: "It's hard to put into words the frustration I've suffered while I've been out, and equally how good it feels to be out there playing again. It's been a tough 17 months and I've been kept going by the thought of days like this."
O'Neill added: "I'm delighted we're still in the Cup and, after a sloppy start, we deserve to still be in the hat. Fraizer came on and gave us the urgency we'd been missing."
Tony Mowbray called on Middlesbrough fans to turn out in force for the replay a week on Tuesday to help his side's bid to clinch a place in the next round after the Championship promotion-hopefuls saw a stunning first-half goal from Scotland midfielder Barry Robson cancelled out by Campbell's strike on the hour.
Middlesbrough have struggled to attract decent crowds to the Riverside in the league this season, and manager Mowbray said: "I've got to give my players credit for that performance, and the great spirit they showed because it's only a couple of weeks ago that Sunderland were beating Manchester City.
"We could have lost a bit of heart after handing them the equaliser to them on a plate, but to their credit the lads came back and showed tremendous spirit.
"We've found it easier to get results away from home this season, but I'd like to think that the people of Teesside would turn out in greater numbers than they have in the league and hopefully that will make the difference.
"We'd love to progress as far as we can, and it should be a replay that's worth following. The draw for the fifth round makes it even more attractive."