Police are monitoring Covid-19 protest convoys heading towards Wellington from both ends of New Zealand.

A spokesperson said they are not following the convoy, but are watching out for any issues using CCTV and units already on the ground.

All kinds of motor vehicles from trucks to cars and campervans are travelling the length of the country to meet in Wellington in protest against Covid-19 vaccine rules and public health measures.

"We are fighting for New Zealand's freedom," read a poster on the Convoy 2022 NZ Facebook page.

Supporters on foot are seen holding up signs on overbridges in Auckland including Wilks Rd and Bawden Rd on Sunday.

Vehicles set out from Cape Reinga in the North Island and from Bluff in the south, starting 6.30am on Sunday, according to the poster.

A Spotify playlist the convoy organisers made for others to add "good tunes to drive to" was taken over by people who opposed the protesters.

"Some people are adding some really disgusting music (don't think you can call it music). I'm guessing [it's] people that don't agree with the convoy because they have nothing better to do," one person said.

Songs that were added by those opposing the convoy included 'Redneck Piece of White Trash' by Rebel Son, 'Why Don't You Get A Job' by The Offspring, and 'Dumb F**k' by Peaches.

The North Island convoy is due to arrive in Wellington on Monday night and the South Island group is scheduled to reach Picton sometime that same day before getting the ferry across.