Australian officials are expressing concern over death sentences handed to six of its citizens in Indonesian for drug smuggling. Indonesia's use of the death penalty is a cause of concern in Australia, which does not execute criminals.

Australian officials urged clemency Thursday for six of its citizens facing the death penalty in Indonesia for drug trafficking.

Indonesia confirmed Wednesday that the Supreme Court had rejected an appeal by four Australians, instead handing down even harsher sentences.

The four were among nine people convicted last year of trying to smuggle heroin to Australia.

The two leaders of the trafficking ring have already been sentenced to death, and their sentences upheld.

Two others in the group face life sentences and the ninth member is serving a 20-year sentence.

The Australians now have two legal options. One is a judicial review, used if there is new evidence or the judge was in error. The second is a direct appeal for clemency to the Indonesian president.

Steven Barraclough, spokesperson for the Australian Embassy in Jakarta, says his country has voiced objections to the use of capital punishment throughout the case and would appeal for clemency.

"The Australian government would support sentences being reduced to custodial terms if the death penalty still stood at the end of the appeals process and they applied for clemency," said Barraclough. "So at the right and appropriate time, we would seek presidential clemency."

Tim Lindsey is the director of the Asian Law Center. He says it is also possible to call for a constitutional review to evaluate if capital punishment violates Indonesia's constitution. Such a move could delay the executions for a few years.

But Lindsay says the group's sentences are not particularly harsh or unusual in Indonesia.

"These people are receiving sentences that, whether you like them or not, are in the range," he said.  "And they're not particularly complex cases, the evidence is overwhelming, all the positive aspects of the Indonesian court system and all the negative inefficiencies and blunders of the normal court system are being seen in these cases. There's nothing special or unusual about any aspect of it in my view."

Harsh sentences handed to Australians in Indonesia have in the past caused a public outcry in Australia, which does not administer capital punishment.

Australians also accuse Indonesia of double standards, comparing the death sentences to the jail terms handed down to extremists convicted of bombings in Bali in 2002 and 2005. Eighty-eight Australians died in the 2002 blasts, which killed 202 people, and four were among the 20 who died in the 2005 bombings.

In June, Australia expressed its concern when Indonesia released a radical Muslim cleric jailed for his role in the 2002 Bali bombings.

On Thursday a court in Bali sentenced two militants for their roles in the 2005 bombings. One was sentenced to 18 years in prison for assembling the bombs and the other to eight years for helping the mastermind of the attacks.