The government department in charge of Northern Ireland's tap water supply until last April spent almost £180,000 on bottled water in three years.

The assembly heard the Department for Regional Development went through gallons of mineral water between the financial years ending 2005 to 2007.

Environment Minister Arlene Foster has ordered an end to office water coolers following a bill of £183,559.

The DRD says it is also phasing out the provision of bottled water.

The figures were given in response to a question from DUP assembly member Sammy Wilson, who said the cost was unacceptable.

"I find it amazing that the department which is actually in charge of the Water Service doesn't have enough faith in the product which it produces that it has to go out and spend almost £180,000 on bottled water," he said.

"What example is this to set to people? Is the water that comes through the taps not good enough, is that what civil servants are saying?"

The government was in charge of the Water Service until last April, when it became Northern Ireland Water. Although it is still government-owned, it is now run privately.