Staff at some Pandora franchises have been told not to call in sick for the next three weeks as the retailer embarks on its busy Christmas period.

In a video sent to staff, Joseph Howley, the head of The Howley Group, the franchisor of some New Zealand and Australian Pandora stores, said staff should not call in sick or cancel shifts because the company was going into a "very busy" time of the year.

Howley can be seen in the video saying: "You are very important to this business; don't call in sick - if anyone is calling in sick cancelling shifts I need to know about this, you need to talk to me directly.

"Unless you have something serious then you're not supposed to do that - for the next three weeks, after that, you can do whatever you want no problem. But those three weeks I need your full support. Is that clear?"

A spokeswoman for Pandora said Howley was not asking staff to avoid taking leave over Christmas.

"While it was not communicated effectively, in the video staff were being asked to contact The Howley Group directly in the event that they cannot attend their allocated shift, in order to best manage alternative arrangements," the group said.

"The video is not aligned with our overarching approach at Pandora."

Pandora had discussed the video "at length" with Howley, the spokeswoman said.

Employment lawyer Catherine Stewart said staff were entitled to take sick leave as needed under the Holidays Act, and an employer could not "contract out of those entitlements".

"Employees do have an entitlement to sick leave, and employers can't require them not to take their entitlements, because that would be contracting under the Holidays Act," Stewart told the Herald.

Stewart said it was unwise for employers to discourage staff from using sick leave when they were unwell.

"We live in an environment where we have a pandemic and so it is a heightened responsibility on employers to make sure that their staff aren't coming to work if they are sick."