Today marks the 50th anniversary of the Strongman Mine Disaster, an explosion that claimed the lives of nineteen men in 1967.

The men were killed when an explosion ripped through a section of the coal mine, which was just north of Greymouth. 

More than 200 relatives, including five of the six remaining widows and their children, have registered for the commemorations.

This morning they'll visit the mass grave site in the Karoro Lawn Cemetery.

On Saturday they'll journey together for the last time to the mine site in the Nine Mile Valley.

Strongman Mine historian and author Peter Ewen said it will be a significant event.

"No-one's going to be around for the 100th anniversary so I think this is the last chance we'll have, participants to the tragedy, will have to get together and reminisce."

Ewen said the poor weather forecast for the day is ironic, as "50 years it was horrendous too."

"It might be all part of the plan from those above to remember the day in question when the funeral took place."