The self-proclaimed 'underdog' of Christchurch's mayoral race will hold an official campaign launch today.

Mayoral candidate and former activist John Minto announced last month he had his eye on the top spot.

Today he'll present all six of his major policies, and explain how he'll make it all happen.

Minto says of those policies, free public transport, will rid congestion and strike out the need for a northern arterial motorway, saving millions of dollars.