An appeal by an Australian citizen against the death sentence for smuggling drugs has been dismissed by Singapore's appeals court.
Nguyen Tuong Van was sentenced to death in March after being found guilty of smuggling about 400 grams of heroin into the country in December 2002.
His only hope of escaping the gallows is to receive clemency from Singapore's President S R Nathan. If the petition fails, Nguyen will be the first Australian citizen to be executed in Singapore.
The death sentence in Singapore, which is mandatory for drug trafficking, is carried out by hanging.
Nguyen was arrested at Changi airport on his way home to Melbourne from Cambodia.
At his trial the 25-year-old was said to have had one packet of heroin strapped to his back and another in his hand luggage when he was stopped for a routine check.
The defence had argued that Nguyen's confessions to Singapore police were inadmissible, the integrity of the heroin presented as evidence was compromised, and Singapore's death penalty was unconstitutional.
All three arguments were rejected by Singapore's three-member appeal court led by Chief Justice Yong Pung How.
His lawyer Lex Lasry QC says he will be appealing for clemency.
"We will of course now prepare an application for clemency to the President of Singapore and the Australian Government has this morning announced through the High Commissioner that they'll support that application," he said.
It could be next year before Nguyen's fate is decided.
Mr Lasry says the bid for mercy could take up to six months to process.
"We put in a petition or an application, it's directed to the President," he said.
"As I understand it, the President acts on the advice of the Singapore Cabinet and it's a process that takes some months.
"I think we've got something like three months to file that application, which of course we will do and it may take another three or so on top of that to make a decision."
Australian High Commissioner Gary Quinlan says the Australian Government will fully support the appeal.
"There are very specific compassionate and humanitarian circumstances which surround this case," he said.
"The Australian Government has always been very conscious of those and we will continue to support the appeal processes for clemency based on that very strong compassionate case.
"Mr Nguyen is an Australian citizen and we will continue to provide him with all the consular assistance we can.
"There still is a decision-making process to be gone through here in Singapore and we don't want to speculate on that because it won't help Mr Nguyen himself."
The Australian Government had previously made high-level appeals to Singapore officials to spare Nguyen, an ethnic Vietnamese from Melbourne, from the death penalty if his conviction was not set aside.
The appeal court's ruling said Nguyen was in "serious financial difficulties" when he was contacted in October 2002 by two persons who asked him to transport a "package" from Cambodia to Melbourne or Sydney.
"It was clear that he wanted to earn money by transporting drugs," the ruling said.
"He flew to Phnom Penh, where members of a drug syndicate provided him with the heroin for transportation via Singapore."
Nguyen had told police he was transporting the drugs to help his debt- ridden brother.
Singapore made the death penalty mandatory for drug traffickers and murderers in 1975.
Anyone caught with more than 15 grams of heroin in Singapore is assumed to be importing or trafficking the drug.
About 400 people have been hanged in Singapore since 1991, mostly for drug trafficking, giving the wealthy city-state of 4.2 million people possibly the highest execution rate in the world relative to its population, Amnesty International says.
Singapore has proven repeatedly that foreigners are not exempt from execution despite potential diplomatic repercussions and criticism from human rights groups.