Fianna Fáil is accusing the coalition of planning to build up an election 'warchest' from the sale of Aer Lingus.
The Cabinet has been briefed on the latest offer from International Airlines Group (IAG), which the board of the former national carrier looks set to accept.
It puts a value on the company of €2.55 per share, or €1.3bn.
Clare TD Timmy Dooley wants the Government to hold onto their 25% - but he said that the Coalition will not do that.
"To provide the Government with an additional windfall of somewhere between €300-400m within 12 months of an election - you know the kind of pet projects that will be advanced in the various constituencies," he said.
"And I think it's quite obvious that it would facilitate the Government in investing in projects that would be beneficial to some of their members, who are finding it difficult to walk down the street at the moment."