The United States needs to provide extra compensation to settle claims by nuclear-affected Marshall islanders and end a "legacy of distrust", according to a UN report released Tuesday.

The 19-page report prepared by UN Special Rapporteur Calin Georgescu also urged Washington to declassify secret reports on its nuclear testing programme in the Marshall Islands.

The United States conducted 67 nuclear weapons tests at Bikini and Enewetak atolls from 1946 to 1958.

Georgescu's report, compiled following a fact-finding mission to the Marshall Islands earlier this year, will be presented to the UN Human Rights Council on Thursday in Geneva.

Marshall Islands Foreign Minister Phillip Muller and survivors of the 1954 Bravo hydrogen bomb test at Bikini Atoll, which spewed radioactive fallout over many islands, will be appearing at the Human Rights Council.

Georgescu said the report "is neither to apportion blame nor attempt to make a legal pronouncement on the nuclear testing program".

The goal was to stimulate dialogue "between the parties in the spirit of understanding, respect and reconciliation, for the benefit of the Marshallese people".

The Nuclear Claims Tribunal awarded more than $2 billion in personal injury and land damage claims arising form the nuclear tests, but stopped paying after a US-provided $150 million compensation fund was exhausted.

Georgescu said the nuclear testing and experiments "have left a legacy of distrust in the hearts and minds of the Marshallese", but there was an opportunity for reconciliation.

The report noted the dispute between US government scientists and Marshallese officials over the effects of radiation and said "a precautionary approach that emphasises the likelihood of risk over conclusive proof may prove more prudent and protective of rights."

Georgescu's report also said testimony by nuclear test survivors about the psychological trauma from witnessing the explosions and their effect recognised a "serious health concern".

"Although these health concerns are of a different nature to cancer, the fear of radiation itself is no less real."