Regional Development minister Conor Murphy has backed the decision to suspend the department's top civil servant Paul Priestly.
Mr Murphy spoke about the phone call he had with Mr Priestly on Tuesday when new details emerged.
The head of the civil service, Bruce Robinson, suspended Mr Priestly.
Mr Murphy did not give specific details about his phone call, but suggested the suspension related to the Public Accounts Committee's NI Water probe.
"The matters in relation to the Public Accounts Committee (PAC) hearing, the events after that are now a matter of inquiry, so it wouldn't be appropriate for me to go into detail, but suffice as to say I consider the work of the PAC committee hugely important," he said.
"I think they have a very significant task in the public interest in holding departments to account and investigating matters that go on in departments and making reports and ensuring the recommendations of those reports are followed up.
"So any attempt to thwart that process or to have any interference in that process I think is a very serious issue and subsequent to the information I received I expressed my views on all of that to the Head of the Civil Service."
Mr Priestly was suspended on Tuesday pending an investigation into events relating to NI Water (NIW).
The civil service said his suspension was to facilitate the investigation and was not a disciplinary penalty.
Mr Murphy issued a statement saying Mr Priestly's position was untenable.
He said he had been in contact with Mr Robinson, on the issue.
The minister has offered to meet the DRD Committee within weeks to answer questions.
Mr Priestly has been in the job for two and a half years and is the chief advisor to the minister.
His suspension came a day after a UTV investigation which examined Mr Priestly's role in relation to sackings of four NIW board members.
They were sacked by the minister in March after an independent review found they were culpable for a breakdown in procurement procedures which meant that £28.5m of contracts were awarded without being correctly tendered.
However, the UTV programme uncovered documents which purported to show that Mr Priestly, who jointly commissioned the independent review, was given an early draft of its report and asked for changes to be made to it.
Those changes are alleged to have directed criticism on procurement matters away from the DRD and onto the NIW directors.
Mr Priestly then gave evidence about the matter to Stormont's spending watchdog, the Public Accounts Committee (PAC), in July.
At that hearing some members of the PAC raised questions about just how independent the review had been.
BBC Newsline's Julian O'Neill said it was events following that (PAC) hearing which have brought about Mr Priestly's suspension.
"Conor Murphy said he spoke to Mr Priestly on Tuesday by telephone and new information came to light," he said.
"He doesn't say what it is but as a result he considers Mr Priestly's position no longer tenable."
It is known that in the days after the hearing one of the independent review team wrote to the PAC complaining about its line of questioning. That complaint was later withdrawn.
In a statement on Wednesday, the Department of Regional Development said "all matters relating to the Independent Review Team and governance failures at NI Water are subject to an investigation by the PAC, which is due for report in the autumn".
It said Mr Robinson had suspended Mr Priestly pending an investigation into events following the PAC hearing on NI Water.
It added that Mr Murphy would brief the Assembly at the first available opportunity.
"Meetings have been agreed for the minister to brief other stakeholders including the interim board of NI Water and the Consumer Council," the statement added
"The appointment of an interim Permanent Secretary is being taken forward with urgency by the Head of the Civil Service."