First Union organiser Ben Peterson said the second case of a worker being ordered to ignore health advice was further proof Labour should bring in its promise to double statutory sick leave to 10 days by Christmas.
This has been called for by the Greens' workplace relations spokeswoman Jan Logie who said Covid-19 made the move "urgent".
"The difference between five and 10 days off could be the difference between increased community transmission of Covid-19 or not."
Peterson agreed.
"We've got organisers from the Far North to the deep south and I'd say everyday one of our organiser would be dealing with retail staff being forced to go to work while they're sick," Peterson said.
"There's a pervasive culture of sick leave not being taken seriously.
"The Government bringing this in under urgency would signal the importance of it."
The Act Party said the Greens' push showed they would "do anything to advance a hard-left agenda".
Act's workplace relations spokesman Chris Baillie said small businesses couldn't afford five extra days of sick leave on top of "one the highest minimum wages in the world, a new public holiday, 'fair pay' agreements and all of the other costs Labour is adding".
"So far, only 2000 people in New Zealand have had Covid-19. Only the Greens would believe that giving 2.7 million workers five days off is the way to help a handful of people who actually need 14 days off.
"Or maybe the Greens know this idea won't help fight Covid-19 but will do anything to advance a hard-left agenda."
The Greens' workplace relations spokeswoman Jan Logie this morning urged Labour to rush through its election promise of doubling sick leave so it's in place before Christmas.
"The difference between five and 10 days off could be the difference between increased community transmission of Covid-19 or not."
But Minister for Workplace Relations and Safety Michael Wood has ruled out bringing the change in before the summer break.
Wood said the bill would be introduced this year before the House rises but it would go through the normal process of public consultation meaning it would come into force next year.
National's workplace relations spokesman Scott Simpson commended Wood for committing the bill to go through the full consultation processes and criticised the Greens for wanting to push it through under urgency.
"It's no surprise the Greens want to hurry up and spend other people's money. They never miss an opportunity to do that."
Simpson said National would wait to see the draft legislation before taking a position on it, depending on what impact it would have on businesses which had been through a hard year.