Minister for Public Expenditure & Reform Brendan Howlin has warned public service managers that they must improve their management of underperformance.

Addressing a Human Resources conference in Dublin, Mr Howlin acknowledged that the Croke Park Agreement is under enormous scrutiny.

He said it was critical that the agreement be "reinvigorated" to ensure it continues to deliver the required scale of savings and reform.

Mr Howlin said that while downsizing the public service had given opportunities to improve the way business is done, it had also exposed weaknesses in the system.

He said managers need to be held accountable for delivery of results.

If their teams are not performing, he said, managers must be responsible for addressing that underperformance in a speedy and professional way.

The minister outlined a number of achievements under the Croke Park Agreement, including the fall in staff numbers, a reduction in the pay bill, and changes to rosters, working time, sick leave and annual leave.

However, his speech made no reference to the recent controversy over public service allowances costing almost €1.5bn a year, which were left almost entirely untouched for serving staff after a review.