Mooney is at Carrow Road on a one-month loan deal from Reading, which is due to expire after the game against Sheffield Wednesday on April 4. But Canaries manager Gunn is already working on extending his stay.
"We have been very impressed with David since he came here," said Gunn, whose side are now out of the relegation zone.
"I believe he is regarded as the best natural finisher at Reading and you can see why. That's what he's all about - goals - and he has already scored two for us and formed a very good partnership with Alan Gow.
"I have already contacted Reading about the possibility of extending the loan and it's looking positive. We'll have another talk towards the end of the current spell and hopefully we will be able to keep him here until the end of the season. I'm confident that will happen."