But the factory reopened on Wednesday afternoon, with staff who had tested negative to COVID-19, the spokesman confirmed.
More than 50 test results have come back, all of which were negative. Amcor is awaiting the results of the remaining tests.
Victoria recorded an additional seven COVID-19 cases overnight, but none are linked to the state’s identified clusters. The new cases bring Victoria’s total cases to 1670.
Health Minister Jenny Mikakos told a press conference that six of the new cases were from those in hotel quarantine, while another case is under investigation.
Ms Mikakos said she believed there were about eight Amcor workers who are “known to be close contacts” of the employee who tested positive. They would be required to self-quarantine for 14 days.
But she said other staff who were not in direct contact with the man have a “very low risk” of contracting the virus.
“There are a small number of close contacts of this worker, in terms of the proximity of people he was working with on site,” the minister said.
“As a precaution, the company has gone above and beyond and all of the workers there are being tested. This is a demonstration of a system working well, having a business working very closely with our public health team.”
Contact tracing and testing of coworkers began as soon as they heard the staff member had COVID-19, the Amcor spokesman said earlier on Wednesday.
“The company is monitoring the status and wellbeing of all its employees and is in regular communication with them,” he said.
The Australian Manufacturing Workers Union said it was working with the company, union delegates and health and safety representatives to ensure its members “feel safe in their return to work”.
There have been 176 confirmed cases of coronavirus in Victoria acquired through unknown transmission, the Department of Health and Human Services says.
Nine people are in hospital, with two in intensive care. Nineteen people have died from coronavirus and 1569 people have recovered.
Of the total 1670 cases, there have been 1384 in metropolitan Melbourne and 234 in regional Victoria. Several cases remain under investigation.
The total number of cases are made up of 883 men and 787 women. More than 526,000 tests have been processed to date.
with Rachel Eddie
Ashleigh McMillan is a breaking news reporter at The Age. Got a story? Email me at email@example.com