INDEPENDENT TD Michael Lowry, whose vote is crucial to the passing of next week's budget, warned this weekend that there was "no question" of him voting with the government unless the €85m EU-IMF package was fair and prudent.

He expressed serious reservations about the mooted interest rate that Ireland will have to pay for the deal, expected to be announced later today, and said he was concerned that "we may not be playing the hardball we should be" in the negotiations.

An interest rate in excess of 6% "cannot be justified" and he could not support the budget in those circumstances, Lowry said. Questioning whether it was in Ireland's interest to support any deal with such a high interest rate, he said that the terms and conditions of the bailout package would decide whether the budget was passed.

His comments suggest that the strong confidence across the political parties that the 7 December budget will be passed could yet prove misplaced.

"My position is that I'm reluctant to vote for the budget for several reasons. But certainly there is no question of me voting for it if the negotiators on behalf of the state can't do a prudent deal for the country," Lowry told the Sunday Tribune.

The Tipperary North TD said an interest rate of 6.5% on an €85m bailout worked out at €18m a day and it was "not possible" for the state to sustain that. "The bailout has to be on realistic terms that are sustainable. It can't strangle the country," he said.

Lowry said he accepted that the state was negotiating from a relatively weak position but he argued that "our hand is much stronger than is appreciated" because the EU and European Central Bank "desperately needs us to sign up".

He repeated his call for Fine Gael and Labour to support the budget and "not to abdicate their responsibility" as a "government in waiting".

"The country has to be safeguarded and the two main opposition parties have to step up to the plate," he said.

When it was put to him that he had the power to ensure the budget's safe passage, Lowry responded: "I'm acutely aware of my responsibilities as well. I am reluctant to support the budget because I have reservations about a number of aspects and I will be taking the opportunity to discuss those reservations with ministers. But it would be helpful if we were satisfied that the best possible deal was done in the negotiations with the EU and IMF."

The government can count on 80 votes, excluding Lowry and the other independent TD supporting the government, Jackie Healy-Rae, while the opposition also has 80 votes. In the event of a tie, ceann comhairle Seamus Kirk (Fianna Fáil) has the casting vote.