Sunderland have only managed six league goals this season with new signing Stephen Fletcher bagging five, and the sixth coming courtesy of a Demba Ba own goal.
Gardner, 25, has only scored once this season, netting in the Black Cats' victory over MK Dons in the Capital One Cup, but his manager is backing him to find the net on a more regular basis.
"I feel that Craig should have ten league goals at the end of every season - regardless of the number of games that he plays," said O'Neill.
"When I say 'regardless of the number of games that he plays', I mean of course assuming he plays upwards of 25 of course. It would be asking a bit much if he only played eight or nine times!
"But Craig's eye for goal really could be a tremendous asset for us.
"He has got a great shot, he gets into dangerous positions and he hits the ball as strongly and as truly as anyone in the Premier League."
Gardner signed from Birmingham for £5million after an impressive run for the Blues, which saw him net double figures in his final season at St Andrews, however chances at goal have been at a premium this season after he has been forced to fill in at right-back for the injured Phil Bardsley.
O'Neill added: "Playing at full-back, he was unable to get into those forward advanced midfield positions but now he is back in midfield, I will be looking for him to contribute some goals.
"We need goals from other sources, we know that. Steven Fletcher has made a very good start since joining us in the summer but we can't put all the goalscoring burden on one man. Other players have to share the load.
"At the moment we are just not creating enough chances and that needs to change. We know that, we recognise it and we are working hard to find ways of improving it."