The government says the grape and wine industry can continue to operate as an essential business, but strict conditions apply as the country moves to contain the spread of Covid-19.
Some Marlborough people have noticed the hundreds of workers travelling to work in vineyards all over the district, and have questioned whether this was safe in the current climate.
A teacher, Sarah Gray, expressed her concerns to the Ministry of Business Innovation and Employment in a letter.
She wrote that a "very large proportion of staff" were working 24-7 in more than 100 wineries, and travelling between hundreds more vineyards throughout Marlborough and Nelson.
She believed many had come from overseas in the last two to four weeks.
"Most importantly there are local cellar hands, lab workers and harvest contractors who are terrified that they are going to bring Covid-19 back into their households and who cannot quit their jobs for fear they will never work in Marlborough again."
Gray said they were all working crazy hours and the focus seemed to be on getting the grapes in, and not stopping the spread of the virus.
"I am a teacher at a local school and I love a glass of wine, but this is crazy."
New Zealand Wine Growers chief executive Phillip Gregan said the industry, now at peak harvest, was working around the clock to ensure harvest workers complied with tough new health and safety rules.
He said coming to grips with tough new health and safety rules was like trying to build a plane while it is flying.
It had been made clear to grape growers that if they could not follow the rules then they would have to shut down, Gregan said.
"The first requirement from the government is to stop the spread of the virus, so what all our growers and wineries are doing is making changes in their business operations to make sure that directive is met."
Gregan said picking the grapes was the current priority, with the fermenting process secondary.
He said the industry was coping with the same complications afflicting other primary sectors which used seasonal workers who needed to be housed, especially in shared accommodation.
"We have had dozens, if not hundreds of questions from our members about shared accommodation arrangements.
"We have given them the best guidance we've been able to work out at the moment. We've been talking with MPI and we have a number of questions into them but this is a little bit like building a plane while it's flying - everybody is working as hard as they possibly can to make sure that we get it right."
Gregan said members had been advised to take a strict precautionary approach, and to isolate workers so they were not contributing to the spread of the virus.
Industry organisation Wine Marlborough said all parts of the supply chain could continue to operate during Covid-19 level 3 and 4 alerts as essential businesses, excluding cellar doors and restaurants.