Overtime payments by financially-embattled Stormont departments have spiralled to £35,000 a day.
Civil servants were handed an extra £13m after working an incredible 786,000 additional hours in the last 12 months.
Most departments saw their overtime expenditure rise from the previous year — one surged by 60% — despite increasing pressure to slash costs.
The overall bill — which has increased by a fifth — has prompted calls for the Audit Office to investigate the issue.
Ulster Unionist MLA Michael Copeland (below) said he would contact the watchdog immediately. “It is an alarming amount of money, and whether it was justifiably spent will only become clear when the matter is considered by the Audit Office,” he said.
Details of each department’s overtime expenditure were obtained by this newspaper after Freedom of Information requests.
In the 12 months to April, civil servants worked 786,303 hours of overtime, costing a total of £12,920,421 in extra payments.
The highest bill was run up by the Department for Social Development, which spent £3.75m on extra shifts. That figure was up 60% on the 2010/11 spend of £2.3m.
Three other departments — Regional Development, Finance and Personnel, and Agriculture — also spent over £1m on staff overtime.
Mr Copeland, a member of Stormont’s Public Accounts Committee, said he was astonished by the growing overtime bill.
“The most expensive way to fill a position or get a task done is through overtime,” he added. ”The essential question is whether this money was well spent or is it indicative of a system which is out of control?”
The East Belfast MLA confirmed he would contact the Audit Office to ask for a review of overtime payments.
Jonathan Isaby, political director of the TaxPayers' Alliance, said action was needed to tackle the rising expenditure.
“Taxpayers will be disappointed to see this big increase in the overtime bill,” he said.
“Of course there will be occasions where paying overtime is unavoidable, but it is expensive and Civil Service chiefs should be working to minimise it.
“These new figures suggest that serious questions need to be asked about how resources are being allocated.” During 2010/11, civil servants worked 709,636 hours of overtime, costing a total of £10,663,738.
Only two departments recorded a drop in expenditure this time around.
The Department of the Environment’s spend fell by £56,000 to £840,000. It follows a pledge by Minister Alex Attwood to reduce costs after previous stories by the Belfast Telegraph on the issue.
A 44% drop was also recorded by the Department of Health, whose expenditure was sliced from £230,687 to £127,216 last year.
The Department of Justice, which spent £117,287 on overtime, did not have comparison figures for 2010/11.
Overtime at the Department for Social Development rose from 170,233 hours during 2010/11 to 240,558 last year.
A DSD spokesman said: “Overtime is worked by the department mainly to meet the in-year peaks and troughs of demand-led work.
He said overtime expenditure was “carefully monitored across the department”.