A probe into a New Zealand coal mine explosion that killed 29 people in 2010, blames the operator for neglecting safety standards and putting workers at risk.

A royal commission into the blast at the Pike River colliery on November 19, 2010, said on Monday that the South Island mine had consistently recorded dangerously high methane levels. The report said the government should not have let the mine operate until the risks had been assessed.

New Zealand's labor minister resigned after the report was released.

Mining at the location stopped following the explosion and subsequent blasts five days later, and the Pike River Mining Company went bankrupt soon afterwards.

Former chief executive Peter Whittal has pleaded not guilty to 12 criminal counts leveled against him in November of last year. His lawyers say he is a scapegoat.

The Pike River mine became a tomb after the explosions on November 19 and 24 of 2010. The bodies remain underground, because the mine is considered too dangerous to enter.