The "rapid review" into the latest controversy within the CervicalCheck screening programme will investigate the role of officials within the Department of Health.
The chairperson of the review, DCU Professor Brian MacCraith assured patient representatives last night that the review would examine all communications between the screening programme, the HSE and the department.
It follows concern from opposition politicians that the role of the department was not explicitly included in the terms of reference for the investigation.
It emerged over the past week that 856 women did not receive the results of their screening test on time due to an IT issue at a US lab hired by the HSE.
On Newstalk Breakfast this morning, patient advocate Stephen Teap, whose wife Irene died of cervical cancer last year, said Professor MacCraith assured him that the review would examine the communications between the HSE and the department.
"I think the key to all of this is who knew what and when did they know about it and what did they do about it," he said.
The Department of Health and the HSE were made aware of the issue by a woman who has become known as 'Sharon' who failed to receive her results.
"Failure to communicate"
Mr Teap said the review must establish when this happened and "what went on within the two organisations from a communications point of view internally and externally" from that point.
"Every time that we have a problem within CervicalCheck of this current debacle it all comes back to the same thing - and that is failure to communicate," he said.
"So withholding any information at this stage is totally unacceptable and I think the Minister of Health needs to do something about this to enforce the Department of Health to open their doors and share absolutely everything from correspondence they have had with the HSE and also internally within themselves."
He said Minister Harris must support the review team as it investigates his own department.
"We haven't heard a whole lot from the Minister of Health except him explaining when he found out," he said.
"I would be more satisfied if he came out and said the Department of Health has to share everything with Professor Brian MacCraith.
"My fear is that they won't and we do need the support of the minister in order to ensure that the doors are opened up within the Department of Health and all the information that he is looking for is provided."
Fifty two of the women affected by the delay proved positive for the HPV virus after their re-test – with half referred on for colposcopies.
The terms of reference of the review pledged to examine "if, how and when" the issue was communicated between CervicalCheck, the HSE and Department of Health.