Experts are calling on the Ministry of Health to improve its mask-wearing guidelines to ensure New Zealanders are protected against the Delta strain.
They say mask protocols at Auckland's border are inadequate in reducing the risk of aerosol transmission.
The experts from the University of Auckland say the country needs an educational campaign on how to wear masks.
"Many people, you observe them around, are not masking well. Bandanas and scarves are not masking," said Sir Peter Gluckman.
More than a year into the COVID-19 pandemic, you'd think we'd have the hang of masks.
But Sir Peter says because of Delta, we need to up our mask game.
"Aerosol spread can go many metres, not just one or two metres, but much further."
The experts say everyone working and staying at managed isolation and quarantine (MIQ) facilities should be wearing N95 masks, along with health care workers and employees at essential businesses such as supermarkets.
But even if you're not an essential worker, it's important to know not all masks are made equally.
If you're using a cloth mask, the experts say they need to be at least three layers thick - and no matter which mask you use, they need to fit snugly across your face.
And if they're too big there's a trick to it - the knot and tuck method - whereby you fold the mask in half, make a knot, then tuck in the sides.
Medical masks should be replaced after six hours, and cloth masks should be washed daily with soap and hot water.
Sir Peter says this information should be part of a national campaign.
"Masking is going to be an important part of our lives both through the lockdowns and after the lockdowns and even after we open up the country a bit more," he said.
And if you haven't got or made the right mask, it may be time for a new favourite.