Official records show the last time a security guard at Auckland's Grand Millennium MIQ facility was tested, before a recent positive test, was in November.
The Government is in the process of verifying the records, with Ministry of Business, Innovation and Employment's chief executive Carolyn Tremain saying it is checking with the worker's employer, who has their own manual records.
An investigation was launched this week after it was revealed by Director General of Health Ashley Bloomfield that the security guard - known as Case B - had not been tested for Covid-19 since at least mid-March.
When asked, MIQ's Brigadier Jim Bliss was not able to tell media when Case B's last test prior to April 6 took place.
Today, Dr Bloomfield, Brigadier Bliss and Tremain faced MPs during the Health Select Committee.
During questioning from National's Chris Bishop, Tremain said prior to last week's positive Covid-19 test, the worker's MIQ testing record showed he hadn't been tested since November last year.
"That's a six month gap," Bishop said.
All workers in MIQ facilities are supposed to be tested once every 14 days. The person was tested during routine testing last Tuesday, April 6.
Tremain said that in the border testing system, "which not all employers have records in, it shows he was last tested in November".
"We have information in our system but we know the employer also has manual records."
Tremain said they were "in the process of verifying that".
"He is a relief worker, a back up worker, for the security area. I would say he's a regular relief worker from what we understand."
It was confirmed during the questioning that even part-time workers need to be tested every two weeks in MIQ facilities.
The issue has seen Covid-19 Response Minister Chris Hipkins tighten the rules around the logging of MIQ staff Covid-19 testing.
The security guard is one of three workers at the hotel to test positive in recent weeks.