Postbank has announced its decision to enter the Government's Guarantee Scheme.
In a statement, the bank said that 'the guarantee covers all Postbank new and existing customer deposits up to September 2010.'
Postbank CEO Margaret Sweeney said: 'Postbank has decided to participate in the scheme to ensure that our banking customers have the same protection as offered by other Irish banks.
'Postbank is in a strong financial position and is not impacted by the current market turmoil. We have a strong capital and liquidity position.
'The widening of the scheme to include Postbank ensures a level playing field among Irish retail banks in the area of state guarantee for customer deposits.'
Postbank operates banking, savings and investments, and insurance services in 980 post offices across the country.
Ulster Bank, First Active, Bank of Ireland (Scotland), Halifax and NIB have opted out of the scheme.