Department of Finance secretary general John Moran has resigned unexpectedly, only two years after taking command of the Department.

Mr Moran, who spent most of his career in banking, was the first outsider appointed to lead the Department and was particularly close to Minister for Finance Michael Noonan at the height of Ireland’s banking crisis.

In an email this morning to staff in the Department, however, he essentially said his work was done. Mr Noonan said in a statement that he accepted his resignation “with great regret”.

Mr Moran had joined the Department in 2010 from the Central Bank, where he was a relative newcomer. Having taken charge of banking policy in the Department, Mr Noonan promoted him two years later to the post of secretary general. In his statement, the Minister said he valued Mr Moran’s council during difficult times.

“Since John first joined the Department of Finance on secondment from the Central Bank he played a leading role in recapitalising the banking sector and restoring the economy at a very difficult time,” Mr Noonan said.

“Since his appointment as Secretary General he has been involved in every significant decision taken by me throughout the bailout programme, including those decisions which saw Ireland successfully exiting the programme.”

In his email to staff, seen by The Irish Times, Mr Moran said the Minister was happy for him to continue as secretary general until his successor was appointed.

“I returned to Ireland in 2010 wanting to assist in the task of restoring Ireland’s destroyed banking sector and economy to health. I had always viewed this as a mission with a fixed purpose not a long-term venture,” Mr Moran said.

“I would never then have expected to be asked to play such a central role and have been very honoured to play my part as head of this Department, working with you all, other public sector colleagues, the Minister and the Government,” he added.

“With the tremendous results captured in our annual report published this morning and the successful completion of last week’s first post programme troika mission, for which I thank you all, I believe it is now an opportune time to hand over the baton to a successor who can continue the job well under way.”

Mr Moran is due to appear before the Oireachtas Public Accounts Committee tomorrow to give an annual review of the department's activities.

Mr Moran joined the Department of Finance in March 2011 and was second secretary in charge of banking. He was appointed secretary general in December 2012.

A lawyer by training, Mr Moran previously held senior roles with Swiss financial group Zurich Capital Markets and is a former head of wholesale bank supervision at the Central Bank.

He is also a member of the advisory committee of the National Treasury Management Agency.