A homicide inquiry should have been carried out into the death of a scientist in Antarctica, according to an internal report for the elite American agency accused of stonewalling New Zealand police over the case.

The internal report is referred to in documents from the inquest into the death of Rodney David Marks, 32, an Australian astrophysicist, who died in Antarctica under mysterious circumstances.

The Herald on Sunday was last week granted access to the documents, which reveal heavy drinking and drug use at the American-run Amundsen-Scott South Pole Station.

The documents come from the New Zealand inquiry into Marks' death in 2000, which began after an autopsy in Christchurch discovered he had been poisoned by a fatal quantity of methanol.

They detail eight years of "legal, diplomatic and jurisdictional hurdles" faced by police - and have led to new rules being developed to deal with sudden deaths in Antarctica.

In the files, the officer investigating the case, Detective Senior Sergeant Grant Wormald, testifies that he was stonewalled dealing with the US National Science Foundation, which runs the base through its polar programme.

Wormald was trying to get copies of the foundation's inquiries into Marks' death, and contact details for the 49 other people who spent winter at the South Pole that year.

Letters reveal no foundation inquiries were provided to Wormald and the agency would not provide contact details for witnesses - only forwarding a questionnaire after approving the questions.

Wormald managed to get hold of one inquiry from a former employee. The report, by a foundation doctor, stated "when an individual aged 32 years dies unexpectedly, the matter warrants a homicide investigation".

The doctor said the inquiry should be carried out even though there was no evidence to suggest murder - or that the death was an accident.

Despite the advice, South Pole station staff were left free to clean Marks' room, disposing of potential evidence as rubbish.

The foundation also did nothing to halt the 49 people leaving Antarctica from disappearing across the world without being interviewed after landing in New Zealand.

Wormald's inquiries led to the US State Department contacting New Zealand's diplomatic arm, the Ministry of Foreign Affairs and Trade, to try to find out why Wormald was being so persistent in his inquiries.

The difficulties were such that McElrea said investigation rules needed to change - a process New Zealand police last week said was underway through discussions with the ministry.

Wormald's investigation revealed a culture of heavy drinking and drug use by some of those spending the winter at the South Pole.

Testimony was given by some witnesses of cannabis being grown, and a stash of marijuana being found at one of the base's large telescopes.