The Sinn Fein president, Mr Gerry Adams, has called for a meeting with the Minister of Regional Development, Mr Gregory Campbell, to discuss the contamination of Belfast and Lisburn water supplies with the cryptosporidium bug.
A Sinn Fein delegation, led by Mr Adams, held a meeting with the North's chief medical officer, Dr Henrietta Campbell, at Stormont yesterday after which Mr Adams called on the Regional Development Department and the Water Service to accept responsibility for the outbreak.
"Sinn Fein will be meeting the head of the Water Service and we are calling for a meeting with the Department and Minister Gregory Campbell. The number of people affected and the anxiety caused by the outbreak and the way it was dealt with cannot be repeated," Mr Adams said.
Some 100,000 people in the greater Belfast and Lisburn areas remain at risk from the bug, which causes severe diarrhoea, stomach cramps and nausea. Over 80 cases have so far been officially reported, but health experts believe the real figure could be several hundred.
People in Poleglass, Twinbrook, Dunmurry and Lisburn are still advised to boil all their drinking water.
On Wednesday, the chief executive of the Northern Ireland Water Service, Mr Robert Martin, told an extraordinary sitting of the Assembly's regional development committee that his officials had identified a private septic tank as one possible cause of the outbreak.
The tank had breached the 110-year-old brick-built water conduit at Lagmore Reservoir, possibly causing an overflow of contaminated water into the system, he added.