The Australian government has confirmed it is looking into the case of a 95-year-old Perth woman accused of looting artefacts from countries including Egypt.

Monica Hanna of Egypt’s Heritage Taskforce posted an open letter to Australia’s ambassador to Egypt, Neil Hawkins, on Facebook this month, alleging Joan Howard spent most of her time during her husband’s diplomatic trips looting archaeological sites.

Howard’s husband, Keith, held senior roles with the United Nations in the Middle East in the 1960s and 70s.

Hanna said Howard had taken advantage of her diplomatic status and her behaviour was “not acceptable”.

“I demand that an investigation should be carried out on the sources of Mrs Howard’s collection now in Perth,” she wrote

She shared a link to a Seven West Media story originally headlined “Indiana Joan and her trove of artefacts”, which described the former nurse as “WA’s real-life tomb raider”.

“There is a mischievous twinkle in the great-grandmother’s eye as she reveals why she has humbly kept quiet about her derring-do,” the article read.

“You don’t go round saying ‘I’ve been in a tomb’,” Howard said.

Hanna said the celebratory tone of the story sent a very negative message, especially given the large amount of looting of Egyptian archaeological sites in recent years.

“These activities decontextualise the cultural heritage and transforms the archaeological finds from historical objects to mere aesthetic artefacts,” she wrote.

“The illegal market leaves the Egyptian cultural heritage with holes that cannot be filled, and many stories that cannot be told about the past.”

The Department of Foreign Affairs and Trade said it was investigating the matter and was obliged under Unesco conventions to return foreign cultural items that had been illegally exported from their country of origin.