Labour MP Kelvin Davis has walked the first of seven marathons in seven days to raise awareness about sexual violence as a social problem.

The Te Tai Tokerau MP and supporters set off from Awanui School, just north of Kaitaia, on Sunday morning for the Seven7 hikoi.
They are doing laps around Kaitaia.

"On the first day we actually walked 45 kilometres. We got our measurements wrong," he said in a video posted on Facebook.

Two other groups in Northland are doing the 7Seven Challenge, one in Kaikohe.

"Join in or toot your horn ... we have just got to do it to protect our people," Mr Davis said.

Last year he went on the Men Against Sexual Violence walk from the Auckland Harbour Bridge to Cape Reinga.