AUSTRALIA'S closest neighbour Papua New Guinea has moved to introduce the death penalty - and suffocation is one of the approved execution methods.

The nation's parliament has passed amendments to its criminal code that will allow death sentences for rape, murder and robbery.

Approved ways people can be executed include lethal injection, hanging, firing squad, electrocution and medical death by "deprivation of oxygen".

The move comes on the heels of a series of violent murders and sex crimes in the country this year. In particular, women accused of being witches have been killed in gruesome public show-trials.

In one incident, a young mother was stripped and burned alive in a public market, while in another a former teacher was beheaded.

PNG Prime Minister Peter O'Neill's spokesman justified the measures in a statement.

"These are very tough penalties, but they reflect the seriousness of the nature of the crimes and the demand by the community for parliament to act."

"Which method (of execution is) to be used will be determined by the head of state on advice from the National Executive Council (cabinet)", he said.

The parliament also repealed the controversial 1971 Sorcery Act, meaning those convicted of killing accused "sorcerers" will be sentenced to death,

Prime Minister Julia Gillard expressed her opposition to the death penalty on a visit to PNG earlier this month.

"Australia is universally opposed to the death penalty," Ms Gillard said. "That is not a question about the death penalty in PNG. It is about the death penalty anywhere."

Ms Gillard said Australia would continue its aid relationship with PNG. The program educates children, provides medicine to the sick and has helped reduce infant mortality rates.

Death by hanging has been part of PNG's criminal code since before independence from Australia in 1975, but has not been enforced since 1954.

Australia's Department of Foreign Affairs has been approached for comment.

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