The Freedoms & Rights Coalition protest group, responsible for organising the protest, said it would "be responsible in terms of health and safety and be able to make way for any emergency services, or allow people to use the motorways and streets/exits if need be".
The Tauranga protest started in Paengaroa about 2.30pm and included protesters from Rotorua and Whakatāne.
The group plans to travel about 25km/h and the route includes: Paengaroa along the expressway, Hewletts Rd, Tauranga Harbour Bridge, and will end at the Sulphur Marine Car Park.
Police said they were aware of the protest activity and will monitor activity.
The event is part of a nationwide protest calling on the Government to end lockdowns and abandon vaccine mandates. Protests were happening in Auckland, Wellington and Christchurch.
Auckland Mayor Phil Goff expressed his anger on Facebook this afternoon after he personally encountered protesters on Auckland's Southern Motorway returning from a vaccination drive at Mt Smart Stadium.
"Apart from spreading disinformation and lies about Covid and vaccination and trying to prevent people going into Eden Park to get vaccinated last weekend, was there anything else the extreme anti-vaxxers could do to alienate more people in the community?" Goff wrote.
"Apparently yes. On the way back from Mt Smart Stadium this afternoon where I saw volunteers and medical staff working in the pouring rain to ensure people are protected, I ran into the anti-vaxxers protesting on the motorway.
"Cars across the three lanes of the motorway doing 50kph deliberately blocking people going about their business. Crass and stupid but what else would you expect!"
A Waka Kotahi spokesperson said traffic operations centres would be closely monitoring highways and supporting police today.
The protest group is associated with Destiny Church, whose leader Brian Tamaki has been charged by police with breaching the Health Act for organising a series of protests at Auckland Domain.
