The sixth floor of the Liverpool City Council building where they worked has been closed off as the investigation continues

A potential cancer cluster is being investigated by authorities after five women from the same office contracted the same type of cancer.

Liverpool City Council in New South Wales, Australia, has confirmed that five current and former members of staff have developed thyroid cancer in the last three or five years – all of whom sat closely to one another in the office.

Four of the five women are taking part in the investigation by the NSW Department of Health and the sixth floor of the building where they worked has been closed off as the investigation continues.

More than 40 employees who worked on the sixth floor have been relocated.

According to reports, there’s a sixth person that’s reported a thyroid condition but they did not wish to take part in the investigation.

Jenny Havilah is one of the people who worked there and ended up contracting thyroid cancer. She believes there’s something ‘sinister’ to the five cancer diagnoses.

Speaking to 9News Australia earlier this month, Havilah confirmed that she’s now had her thyroid removed and was waiting for the results.

She continued to tell the news outlet: “I’m worried about my colleagues not just on the sixth floor but that worked anywhere in that building.”

Jenny Havilah was recently diagnosed with thyroid cancer. (9News)

Liverpool City Council has since spoken out in the wake of the cancer cluster probe.

“The decision to relocate staff is in response to the council’s high level of concern for the welfare of its staff,” it said in a statement, as per 7NEWS.

“Council takes this very seriously and future action will be based on the results of the two concurrent investigations.

“Our thoughts are with those affected and we wish them a prompt recovery.”

While staffers have been moved from the potential hazardous floor, the United Services Union (USU) has called for the building to be shut down completely.

The women all worked in the same office. (9News)

USU acting general secretary Daniel Papps told 7NEWS: “We’re concerned the issue may be more widespread so we’d be waiting for an independent medical assessment to unequivocally clear the area before we would be recommending our members return.

“We have to remember we’re talking about a workforce that over the last couple of years has become used to remote working… so I don’t think it’s necessarily a significant stretch to say the office building itself should be cleared.”

Papps added that staff members were ‘extremely concerned’ about the situation.

It’s said that the council has engaged an independent third-party environmental health consultant. Meanwhile, the state’s health department is running its own separate epidemiological investigation.