McDonald's has banned keep cups in its cafes in an attempt to stop the spread of coronavirus.
A McDonald's spokesman told Newshub it will not be accepting the reusable cups in an effort to protect customers and staff.
But at a press conference on Wednesday, Director-General of Health Dr Ashley Bloomfield would not comment on how effective such a precaution would be.
"If you've got your keep cup and you're going out for a coffee then you'd assume you're well," he told reporters. "It comes back to if you're not well, you're not going to be using your keep cup."
The McDonald's spokesman said it's a measure that's also been taken by some other cafes.
Meanwhile, a spike in cases has led to Australia adding Italy to its travel ban.
Prime Minister Scott Morrison said the decision mirrors Italy's lockdown.
"Effectively, though, I think it's important not to overstate this," he told reporters on Wednesday.
"Italy itself has effectively put itself into lockdown with travel now - this largely closes that loop."
Dr Bloomfield advised all New Zealanders to "please stay at home" if they are feeling unwell, regardless of the severity of their illness.
"It's particularly important for large events, concerts and other mass gatherings," he said during Wednesday's press conference.
More than 9000 people have self-isolated in New Zealand since the outbreak began.
Globally, there have been 113,702 confirmed cases and 4012 deaths to date, according to the World Health Organisation.