Mr Michael Bailey has denied that he ran an "open bar" for county councillors at Conways pub in Parnell Street, Dublin.
The Bovale director agreed that he visited the pub, which was a common meeting place after Dublin County Council meetings.
He said he went there to explain his case for planning permission to county councillors who might not have been in favour of a particular project. "I don't deny that I lobbied councillors. It's hard work but it's a part of life," he said.
Mr Bailey said that he bought drinks for councillors as a courtesy but never ran a tab in the bar. He said that he would have paid for the drinks by cash or cheque at the end of the night.
Mr O'Neill suggested that the property developer was running an open bar for councillors. "I was not running an open bar in Conways. Jesus Christ, what's wrong with you?" he said, to laughter from the public gallery.