Credit rating agency Moody's has upgraded the debt ratings of four Irish banks - AIB, Bank of Ireland, Permanent TSB and EBS.

This follows the agency's upgrading of Ireland's government bond ratings to Baa1 from Baa3 earlier this month - the second upgrade from Moody's in six months.

Moody's also changed its outlook for the country from stable to positive.

It said the government-guaranteed debt ratings of the four banks has improved to Baa1 from Baa3, while  the outlook on these debt ratings changed to stable from positive. 

In a statement, it said that all other ratings of the banks including the deposit ratings, senior and subordinated debt ratings are unaffected by today's action since their standalone bank financial strength ratings (BFSRs) remain unchanged. 

The other Irish bank ratings are also unaffected by today's action.