Finance minister Brian Lenihan has sanctioned the payment of at least €10m to consultants since last September to advise the government on the banking sector crisis.

Lenihan has admitted that, following his request, the National Treasury Management Agency (NTMA) hired consultants last September on a flat retainer fee of €2m. The contract, which expires next month, allows for an overall payment of a maximum of €6m.

Though Lenihan said that the NTMA did not wish to reveal names or contractual details for confidentiality reasons, Labour's finance spokeswoman Joan Burton said the consultants involved are international financial consultants Merrill Lynch.

Lenihan also said the NTMA had contacted a number of investment banks to provide the urgently required advice but all declared a conflict of interest.

"This is an outrageous amount of taxpayers' money to spend on economic mumbo jumbo," said Burton.

"A lot of that advice could have come from the minister's own staff at no cost to the taxpayer. Last October, the minister declared a fatwah on hiring external consultants but he isn't following his own rules," she said.

Lenihan also said that the NTMA has retained "an economist" to advise the agency but again was reluctant to divulge details.

"I am advised by the NTMA that the terms of his contract with the NTMA were agreed on a confidential basis," said Lenihan.

But Joan Burton again named the economist as Peter Bacon, who has done consultancy work for the government before, particularly on the housing market.

The NTMA did not respond to questions concerning Bacon's remuneration.

"Only last week, economists Patrick Honohan and Karl Whelan told a Dáil committee that one of the key aspects of successfully tackling the banking crisis is transparency. Yet we are not told how much Peter Bacon is being paid or given the details of the multi-million consultancy contracts," said Burton.

Lenihan also admitted that another agency under his remit, the Financial Regulator, has paid consultants €3.8m to advise the government on the recapitalisation of the banks. Though Lenihan again declined to name the company, a spokeswoman for the regulator confirmed the company as PWC consulting.

It produced the now infamous PWC report on the banks just before Christmas which minister Lenihan later admitted he had not read in full despite paying €3.8m for it.

The regulator spokeswoman stressed that the €3.8m fee paid to PWC will be recouped from the banks.

The regulator has also asked PWC to carry out a further analysis of "certain specified" banks covered by the €400bn state guarantee scheme while PWC is also doing a separate "due diligence" study of AIB and Bank of Ireland for the National Pensions Reserve Fund Commission. Both projects are ongoing and contractual details were not disclosed.

This puts the consultancy bill for the banks crisis at €10m so far, excluding vat and expenses, Bacon's fee or the cost of the two PWC contracts above.