Death sentence concerns PM

Prime Minister Helen Clark has registered with Singapore's Prime Minister New Zealand's concerns about the planned execution of Australian drug trafficker Nguyen Tuong Van.

She talked to Lee Hsieng Loong in Malta at the Commonwealth Heads of Government Meeting.

"She raised the matter informally, making her concerns known to him and her views on capital punishment," a spokeswoman for the Prime Minister said.

Nguyen is facing execution on Friday under Singapore's tough anti-drug laws after being caught with nearly 400g of heroin.

Despite repeated pleas from Australia to consider clemency for the 25-year-old former Melbourne salesman, Singapore is standing firm on the decision to execute Nguyen.