An expert says she's delighted mask advice is being reviewed as Omicron arrives in the community

Director-General of Health Ashley Bloomfield says officials have been reviewing evidence from overseas around masks.

He says n95 masks are very good -- but must be worn properly.

Otago University senior research fellow Lucy Telford Barnard says respirator masks - n95 and P2 masks - are the best option for people.

She says they're more likely to fit straight out of the box and provide excellent filtration.

Telford Barnard says most people picking up a surgical mask and putting it on will have much more leakage than doing the same with a respirator mask.