Northern Ireland Regional Development Minister Conor Murphy faced new demands to quit today following a Christmas and New Year water crisis.
With Laurence MacKenzie, the chief executive of the water company at the centre of the fiasco, expected to step down as early as this afternoon, pressure mounted on Mr Murphy to go as well.
A meeting of the Northern Ireland Water (NIW) board in Belfast this afternoon is expected to discuss Mr MacKenzie's future as a £250,000-a-year boss following public outrage over his handling of the emergency which left up to 60,000 homes without water at various periods over the holiday.
Nationalists and unionists have called for Sinn Fein minister Mr Murphy's resignation.
SDLP Assembly member Conall McDevitt said: "Many will question now how long Minister Murphy's position that he is the only one who is blameless in the long line of disasters to hit his department and its agencies is really sustainable."
A spokesman for NIW said Mr MacKenzie, who has held the post since 2009, had "not tendered his resignation".
Environment Minister Edwin Poots said it was right that he should be considering his position but added that others in the organisation should also take the blame.
Tens of thousands of homes and businesses were left without water when Arctic weather around Christmas was followed by a swift thaw that ruptured pipes.
But NIW failed to cope with the public outcry for information and is accused of bungling efforts to help stricken families.
Ahead of Mr MacKenzie's impending resignation, a leading critic said the chief executive should first give a full account of the crisis to a Stormont scrutiny committee he is expected to address on Thursday.
Stormont Regional Development Committee member Mr McDevitt said Mr MacKenzie had a duty to be accountable to the committee.
"If he was to resign before Thursday, that would be a dereliction of his duty," he said.
The representative for the nationalist SDLP also said Mr Murphy had questions to answer, regardless of Mr MacKenzie's future.
"Many questions still remain unanswered about the role he and other individuals within NI Water, the Department of Regional Development and the Minister himself have played in this entire fiasco of the recent water crisis," he said.
"But Mr MacKenzie's resignation will not be the end of this matter.
"It is noticeable the minister has now presided over the departure of three NI Water chief executives, the dismissal of four board members and the suspension of his permanent secretary.
"Many will question now how long Minister Murphy's position that he is the only one who is blameless in the long line of disasters to hit his department and its agencies is really sustainable."
Sinn Fein has accused opponents of scoring political points over the crisis, but Mr McDevitt said Northern Ireland Water had been dogged by controversy under Mr Murphy.
The minister has promised an independent inquiry into NIW's performance, which First Minister Peter Robinson branded "shambolic".
Mr Murphy has said the terms of reference of the latest inquiry are close to being agreed and the review will not be barred from examining the performance of his department.
NIW is a Government-owned company and operates as a so-called arms-length body under the responsibility of the Regional Development department.
It has said it is closing down the final water leaks. Yesterday it reported that just over 100 properties were without water.