The former Republic of Ireland international believes that the former Celtic and Aston Villa manager would be a "good choice" for Ireland boss
O'Neill initially emerged as the firm favourite to take over the reins when it was announced that Giovanni Trapattoni had departed by mutual consent and former Republic of Ireland international Keane believes that the 61-year-old would be positive appointment.
"I know a little bit about Martin O'Neill and I think Martin would be a very, very good choice," Keane told reporters at the Mayfield Community Volunteer Awards in Cork.
The 42-year-old, who was capped 62 times for Ireland, also praised the Football Association of Ireland (FAI) for taking their time to assess the market, noting that there are a number of good managers currently available.
"I think the FAI have done the right thing in stepping back, taking their time and seeing what is out there," added the former Manchester United midfielder. "A lot of managers have been linked with it. A lot of good managers."
Keane himself is also believed to be among the candidates in the running for the job, with the Cork native currently out of work following spells with Sunderland and Ipswich Town. However, he revealed that he had not been contacted and admitted that he had not given the idea much thought.
"I haven't been contacted by anyone," said Keane. "I have not thought about it too much to be honest with you. I have more important things to be worried about."