A third explosion has hit the Pike River coal mine in New Zealand almost a week after the first explosion apparently killed 29 miners trapped inside last Friday.

The explosion happened moments before families and friends of the men and emergency services were to hold a minute’s silence to mark one week since the first explosion.

All hopes that the miners may have been found alive were dashed when a second explosion rocked the mine on Wednesday.

The mine company’s chairman said no one was hurt in the latest explosion.

Prime Minister John Key has warned it may take months to recover the men’s bodies from the highly combustible environment inside the mine and pledged that an inquiry would “leave no stone unturned” to discover what caused the explosions.

TNT is holding a benefit day for the Pike River Relief Fund Trust on December 5.