SIPTU's next vice-president is expected to be Mr Jack O'Connor, the union's regional secretary for the midlands and south-east.
The count does not take place until today, but tally results when boxes were opened yesterday suggest he secured around 60 per cent of the vote.
The next highest vote went to Ms Carolann Duggan, the Socialist Workers Party shop steward who has contested the last four elections for general officers in SIPTU on an anti-partnership stand. It was unclear last night whether SIPTU's regional secretary for the Dublin private sector, Mr Jack Nash, or Galway-based academic Ms Nuala Keher would come in last.
At 43 Mr O'Connor represents a new generation within the union. The current general secretary, Mr John McDonnell, is due to retire in 2 1/2 years and the president, Mr Des Geraghty, a year later. Mr O'Connor can expect to succeed Mr Geraghty as president and could spend the next 17 years at the helm of Ireland's largest trade union.
Despite his youth, Mr O'Connor has been an active trade unionist since the age of 15. He was a shop steward at 18 and a branch secretary at 23. He is married with three children and lives in Naas. He is a native of Lusk in north Co Dublin.
While Mr O'Connor is seen as one of the old school of self-taught trade unionists, who is a strong supporter of the Labour Party left wing, he has also been involved in pioneering major partnership deals.
This has not stopped him from being highly critical of the Programme for Prosperity and Fairness, and he has called for an early review of its pay terms.
The total poll is expected to be under 100,000, compared with 110,000 votes, or over 60 per cent, when Mr McDonnell was elected in 1998. Union sources put the low poll down to election fatigue.