Waka Kotahi is warning of possible delays on the Auckland Harbour Bridge. Photo: RNZ / Marika Khabazi
Waka Kotahi says a convoy of about 10 tractors is heading towards the city at 60 km/h causing mild congestion.
A spokesperson said the group entered the motorway at Drury.
Motorists should consider using the Western Ring Route as an alternative if travel over the Harbour Bridge is disrupted.
The farming advocacy group said once the convoy has crossed the bridge the group will turn around and continue through downtown Auckland.
Spokesperson Bryce McKenzie said the group was worried about the mental health of farmers, with a latest survey finding it was at an all time low.
McKenzie said the protest action was kept quiet in the group to avoid a big disruption.
