The government is due to announce its future plans for the levy when it presents its 2024 budget next Tuesday.

The measure raised a flat 150 million euros a year after its introduction following the banking crisis a decade ago, dropping to 87 million euros last year after two of the country's five retail banks announced they were leaving the market.

Sinn Fein said it would maintain the levy, which is based on the size of each bank's deposit volumes, and tailor it to make sure it raises 400 million euros next year. Last year it proposed raising 150 million euros from the measure.

The yield in future years, when the left-wing party may be in power, would depend on the banks' level of profits.

"In 2019 we were taking in 150 million euros and the banks at that time had profits of 2.1 billion. Today they're expected to have profits of 5.1 billion euros (in 2023)," Sinn Fein's finance spokesperson Pearse Doherty told a news conference.

"We think it (400 million euros) is appropriate."

The pro-Irish unity party has a wide lead across all opinion polls ahead of a parliamentary election that is due by early 2025 but could be called as soon as a year's time. Polls also suggest it may need one of the two large rival centre-right parties currently in government to form a coalition.

Sinn Fein said it would use part of the proceeds of the bank levy to temporarily absorb 30% of the increased interest costs any homeowner has faced since interest rates began to rise, to a maximum benefit of 1,500 euros.

The government is also considering targeted mortgage interest rate relief.

Sinn Féin's alternative budget also repeated previous promises to cut taxes for low-income earners, increase them for individuals earning more than 140,000 euros, phase out a tax levied on primary residences and freeze residential rents.

(Reporting by Padraic Halpin; Editing by Gareth Jones)