After leaving politics, O'Mahony became a public affairs consultant in 1989. He was also an Associate Lecturer in European Studies at the
Institute of Public Administration in Dublin. O'Mahony later became known as the "public face" of the Irish Tobacco Manufacturers Advisory Committee (ITMAC), of which he was director and which shared an office in Dublin with O'Mahony's company CIPA; in 1992 O'Mahony's name was recorded as the donor of
IR£3,000 donated to the
Progressive Democrats on behalf of ITMAC. As a lobbyist against plans for legislation to protect workers against passive smoking, O'Mahony was named in 1999 as having been involved in lobbying by ITMAC which Dr Fenton Howell, vice-president of the
Irish Medical Organisation, claimed "secretly manipulated and misled a group advising the minister for health on new smoking regulations". After hearing O'Mahony's evidence, the chairman
Batt O'Keeffe told Mahony that some of the points made about his conduct were "well-founded", and recommended that "in future deliberations he would be conscious of the public interest and people's health". Howell told a sub-committee in 2001 that O'Mahony had been "less than candid in his replies" to the committee. O'Mahony was one of three former senior officials of the Irish Labour Party reported to have had ties with the tobacco industry. ==Personal life and death==