Opposition candidates in the Tipperary South by-election yesterday challenged the Taoiseach to confirm that the constituency would benefit from decentralisation.
However, Fianna Fail said there would be no announcement on the issue until the end of July.
The failure of Tipperary South to be selected for a decentralised Government department has been a major issue of the by-election campaign.
On a visit to Tipperary town yesterday, the Fine Gael leader, Mr Michael Noonan, said the constituency deserved to benefit from decentralisation and the people were entitled to know when this would happen.
He said 500 civil servants were looking to relocate to jobs in Tipperary South. Fine Gael would bring forward proposals before the next general election to encourage the private sector to decentralise, too, he claimed.
The Labour candidate, Mr Denis Landy, said voters were told during last year's by-election that a programme of decentralisation would be announced after the campaign.
"In addition, I want the Taoiseach to inform the people what Government department he plans to move to south Tipperary, how many civil servants are involved and what union has agreed that its members will be relocated," he said. "If the Taoiseach cannot answer these simple questions then it is clear Fianna Fail are engaging in yet another election stunt."
In an open letter to the Taoiseach, the independent candidate, Ms Phil Prendergast, said a decision to decentralise 750 jobs to the constituency should be made immediately.
She said the Workers and Unemployed Action Group, which she represents, would not accuse Mr Ahern of auction politics if he announced this and other badly-needed jobs initiatives. "We will leave that line to Labour and Fine Gael who were also in government for many years and equally neglected south Tipperary."
The Fianna Fail director of elections, Mr Brian Lenihan TD, said there was no question of an announcement before the by-election.
The Taoiseach had made it clear that decentralisation to Tipperary South was a "top priority", he said, but a decision would be part of a national package on the issue. Opposition candidates would scream "auction politics" if an announcement was made now, he said.
Asked at a press conference to explain Fine Gael's plans to encourage the private sector to decentralise, Mr Noonan said the proposal was not at an advanced stage.
The by-election, to fill the vacancy caused by the death last year of the Fine Gael deputy, Ms Theresa Ahearn, takes place on Saturday. There are four candidates: Mr Tom Hayes (FG), Mr Denis Landy (Lab), Mr Michael Maguire (FF) and Ms Phil Prendergast (Ind). The count is on Sunday.