Byelection will be first Dáil electoral test of Cowen
Sitting senators Maria Corrigan of Fianna Fáil and Labour’s Alex White are expected to be the frontrunners for the seat Mr Brennan has held since 1981.
A former producer of the Late Late Show on RTE, Mr White polled 3,575 first preferences in last year’s general election, ahead of Ms Corrigan’s 3,438.
Mr White was later elected to the Cultural and Educational Panel in the Seanad while Ms Corrigan was one of Taoiseach Bertie Ahern’s eight nominees.
Fianna Fáil will also have to fight the Dáil seat of former Government chiefwhip Tom Kitt at the next election as he announced he is stepping down.
Mr Brennan built up an efficient Fianna Fáil organisation in Dublin South since he was first elected in 1981.
The constituency consistently delivered him one of the biggest first preference votes in the country.
Last year he polled 13,373, more than a third over the quota of 10,201.
Mr Brennan’s Fianna Fáil organisation is certain to put forward a candidate for the byelection, which may not take place until well into 2009.
