Antarctica New Zealand says Brazil should have been quicker to advise its treaty partners about the sinking of a barge carrying thousands of litres of fuel.
The Estado de Sao Paulo newspaper has reported the barge sank off the coast of the Antarctic Peninsula in December and has accused the Brazilian government of a cover-up.
The Brazilian Navy says none of the 10,000 litres of diesel on board the boat has leaked.
Antarctica New Zealand chief executive Lou Sanson says he was advised of the accident on Sunday and he doesn't know why there was a delay in reporting it.
The Ministry of Foreign Affairs and Trade says its officials will seek the facts from New Zealand's Antarctic Treaty partners.
The craft is lying in 40 metres of water off the Comandante Ferraz Antarctica Station in Admiralty Bay on King George Island, near the tip of the Antarctic Peninsula.
