Police in East Timor who uncovered a mysterious mass grave at the national government palace last month said Friday they had found the bones of 72 bodies and clues the dead may have been Chinese.

Construction workers discovered the remains of 52 people in a garden outside the beachfront palace in June, which houses the office of Prime Minister Xanana Gusmao, and contacted police.

"There were new bones found on Monday, so now we have 72 bodies," Criminal Investigation Service commander Superintendent Calisto Gonzaga told AFP.

"Some materials were found buried, like drinking glasses, a spoon and plates, so we need archaeologists to help identify them. But by observation, it seems the plate and glasses are from China."

In 1975, Indonesia invaded the former Portuguese colony, starting a 24-year bloody occupation in which an estimated 183,000 people were killed or starved to death.

Gonzaga said he suspected the bones pre-dated Indonesian occupation and could be from World War II, although there were no military boots found, suggesting they were probably civilians. East Timor was occupied by the Japanese during the war.

Gonzaga said he hoped to engage an international forensics team, with experts from Australia, Malaysia, Korea and Thailand to look into the mystery.

Damien Kingsbury, an expert on East Timor at Australia's Deakin University, earlier said if the bones were not Timorese, they were most likely of Chinese people, who were in East Timor before Indonesian occupation.

Kingsbury said Indonesians would not have buried their own people in a mass grave, and that the bodies were less likely to be of Portuguese colonisers.

East Timor voted in 1999 to become an independent nation in a UN-sponsored referendum.