Fianna Fáil’s Barry Cowen has insisted his party is “not compatible” with Fine Gael in Government.

He said Fine Gael “disregards” its coalition partner the Labour Party and everything it “supposedly” stands for.

“There are great differences between us, in case you haven’t noticed, between Fianna Fáil and Fine Gael, in relation to tax, universal social charge, public services, pensions and pensioners, costs to families and water, just to name a few,” he said.

“They’re real differences that people have identified and are identifying. We’re not standing behind the door in our efforts to highlight those differences and to offer the alternative, to offer the change, to offer a new leader in Government.”

Asked on Monday if he would prefer a hung Dáil followed by another election or to form a coalition with Fine Gael, Mr Cowen told a press conference: “We’re not compatible, lads”.

Finance spokesman Michael McGrath the “rip off” treatment of variable rate mortgage holders should be at the centre of the general election campaign.

Mr McGrath said more than 300,000 households were paying rates that were double the European average for equivalent mortgages.

“The Government has failed miserably to deal with this issue. [Minister for Finance] Michael Noonan has huffed and puffed. He’s met with the banks but he’s been bought off very easily indeed,” he said.

Mr McGrath criticised Mr Noonan for accepting new fixed rates being introduced by some banks.

“The plight facing mortgage holders, especially those with high interest rates, is a real priority for this party,” he said.

He said Fianna Fáil would extend mortgage interest relief until 2020 and empower credit unions to offer mortgages.

Mortgage holders should be able to switch easily between lenders to guarantee they always benefited from the lowest rate available.

Renters should get credit when applying for mortgages and this should be enshrined in the Central Bank’s mortgage deposit rules, Mr McGrath added.

Meanwhile, Mr Cowen will be taking part in a deputy leaders’ debate on TV3 on Monday night.

Fianna Fáil leader Micheál Martin did not appoint a new deputy leader after Éamon Ó Cuív opposed his party’s agreed stance on the European Fiscal Compact treaty in 2012.

“It’s only by virtue of who is available, who can make it to Dublin this evening and so forth, that I have been proposed to do that. Nothing else, and nothing else can be read into that,” Mr Cowen said.