The Covid-19 QR code will need to be displayed on public transport from Friday, September 4.
It comes as masks will be also mandatory on public transport from Monday.
The new QR code display rule includes buses, trains, taxis, ferries and ride share vehicles.
Health Minister Chris Hipkins said a QR code display would be "less burdensome" than a physical sign in and was a better option than relying on Snapper and HOP cards as many people did not register them.
He said it would add an "extra layer of assurance and speed to contact tracing ability".
Operators would not have to enforce the use of the QR code.
The display of QR codes are also mandatory for businesses, with Mr Hipkins saying more than 320,000 retail venues currently display the Covid-19 tracer code.
It will be compulsory to wear a mask on public transport at Covid-19 Alert Level 2 and above.
"It's a precautionary approach and it's an important layer to our prevention strategy," Mr Hipkins said.
On if there would be issues with some passengers accessing masks ahead of Monday, Mr Hipkins said three million had been distributed across community organisations to give to people who might not be in a position to buy them.
The Government is also working with supermarkets, he said.