More than 18 months after a 33-year-old was fatally injured in an explosion on Whakaari/White Island, an insurance company has rejected a claim by his grief-stricken family, the ABC reports.

Jason Griffiths spent thousands of dollars on his American Express credit card to buy tickets for the cruise on the Ovation of the Seas to New Zealand and believed he was insured for the entire trip, the Australian news broadcaster says.

More than 18 months after Griffiths was fatally injured in the massive explosion on Whakaari/White Island, the loss of life claim from his family has been rejected on a technicality.

Australian tourists Jason Griffiths, Karla Mathews and Richard Elzer, three friends who died in the White Island eruption. Photo / Supplied, File

Twenty-two people lost their lives – and more than 25 other people suffered serious injuries – when the once-popular tourist attraction exploded.

The ABC reports Chubb Insurance, the underwriting insurer for American Express, has informed lawyers representing Griffiths's family the claim would not be accepted because he was "touring" the island and not travelling to or from the cruise ship.

The NSW man was on the cruise with eight friends, including Karla Mathews and Rick Elzer who were also killed in the December 9, 2019, eruption.

His mother Karen Griffiths told the ABC it felt "like a kick in the guts".

"It's just so wrong on so many levels," she said.

"He had the American Express [card] because of the complementary insurance, which is attached to it.

Whakaari/White Island shortly after the volcanic eruption in December 2019. Photo / George Novak, File

"All they're caring about is people who use their card and get all their money off them in interest and everything else that goes along with it."

A Chubb Insurance representative wrote to the family's lawyers earlier this month and rejected the claim as he was walking on a volcano rather than being transported to or from the cruise ship.

According to the ABC, the representative said the policy covered time spent on the cruise ship, transport to and from the ship or while waiting in a terminal

It did not cover trips during stopovers.

"Chubb previously expressed a view that Griffiths was touring on, or otherwise visiting White Island when he was fatally injured," the letter stated.