Regional council general manager policy and regulation Katrina Brunton said the council is "disappointed to see that people wearing face coverings is at a much lower rate than when it's been required previously" and is concerned people "aren't taking this seriously enough".
"We're seeing a mixed bag of people wearing face coverings – we're hearing reports of as low as 10 per cent on some buses, and high or full compliance on others."
On August 31, 2020, the first day masks were mandatory at level 2, the regional council said about 60 per cent of passengers wore masks.
"We know that at alert level 2 the risk of Covid-19 being present in the community is higher.
"For the health of the community, people must legally wear a face covering on public transport."
Despite masks being mandatory, a police spokesperson said no arrests or fines have been issued for failing to comply.
Police said they have been pleased with "the overall general compliance" by the public when it comes to masks.
"Police work with Ministry of Health and public transport operators to ensure commuters are complying with regulations around wearing face masks.
"Police have adopted a graduated response model, engaging with and educating the public around the regulations.
"We continue to work with the community alongside our partners to ensure commuters wear face coverings to help prevent any potential spread of Covid-19 in the community."
The spokesperson did not say when or if police may start issuing fines or arresting people.
Brunton said passengers without a mask will be advised of the face covering requirement and given a mask by the driver if stocks are available.
"Waka Kotahi stocks are running low, and the regional council is providing 2000 so the buses have supplies."
Drivers are reminding passengers about the mask law, but are not expected to enforce passenger compliance, she said.
"All of our buses have QR codes as well as public information posters about Covid-19 and passengers' responsibilities while travelling on the bus."
Council was not able to give specific numbers for passengers not wearing masks.