Government books were €12.1bn in the red last month, a fall of €6bn on the same time last year, official figures revealed today.
The tax take was €1.9bn lower than the same period last year at €18.9bn, the Exchequer said.
The Department of Finance said three of the so-called big four tax-heads – VAT, corporation tax and excise duties – performed above expectations in the first eight months of the year.
Finance Minister Brian Lenihan yesterday claimed the figures would show that the economy had stabilised.
Joan Burton, Labour’s finance spokesman, disputed his assessment, claiming his credibility was being called into question.
“If the Minister believes his own claims, it can only mean he is dangerously in denial about the real situation in the national economy,” she said.
Ms Burton added: “This Minister has been proven wrong time and again in his assessments of bank losses and his repeated claim of imminent recovery. It has come to a point that his personal credibility is at an all time low and nothing he says can be believed with confidence.”
Officials said the fourth main tax take, income tax, remained behind target at the end of August and added that it was important to note income tax was ahead of monthly targets for both July and August.
The Government said the massive fall in the Exchequer deficit was mainly because €3.8bn was pumped into Anglo-Irish Bank in 2009 along with 3 billion euro for the National Pensions Reserve Fund.
Officials also said a targeted tax take of 31 billion euro for the year, a fall of 6% on 2009, was valid.
But Ms Burton added: “The Irish economy remains in a stagnant state.
“For Brian Lenihan and his fellow Ministers to suggest otherwise is an act of deliberate deception and means they are unfit to hold office at such a dangerous time for our country.”