SINGAPORE - A national service defaulter seeking Australian citizenship was advised by a tribunal in that country to first return to Singapore and face pending offences.

Rejecting his appeal, the Melbourne-based tribunal refused his plea to waive a clearance certificate from the Singapore police required to support his citizenship application.

"I consider the Australian people would reasonably expect that those applying for citizenship would respect laws of general application," wrote senior member A. Nikolic of the Administrative Appeals Tribunal of Australia.

"The existence of verifiable information that an applicant has not obeyed the laws of their existing country of citizenship understandably raises character concerns," he added, in decision grounds issued last week (Nov 22).

Australian permanent resident Ashley Rozario, 25, who was born here, remained in Singapore to complete his polytechnic studies when his parents migrated to Australia in January 2011. He joined them in November 2012, and has been there ever since.

His Singapore passport expired in 2014 but was not renewed as he had not reported for compulsory national service the year before.

However, this decision had an impact when his application for Australian citizenship made in 2015 was rejected by a delegate of the Minister for Immigration and Border Protection in January (2017).

It led to his appeal at a tribunal hearing last month.

The tribunal noted Mr Rozario had satisfied all legislative requirements for citizenship except for the issue of whether he is of good character within the meaning of the relevant Act.

For this, he needed to produce a certificate of clearance from the Singapore police stating he had no criminal convictions, but the police declined to provide him with one as he had "outstanding issues" in relation to his national service liability.

Mr Rozario sought a waiver of the certificate requirement as there were no prospects of getting the certificate or renewed passport.

In 2013, he received an e-mail from the Central Manpower Base that he had committed two offences of having failed to enlist for full-time NS and for remaining outside Singapore without a valid exit permit. He was told that if convicted, he could be fined up to $10,000 or jailed up to three years or both, and was advised to return as soon as possible.

Mr Rozario said he was committed to living in Australia as his whole family was there and he did not have a valid passport to travel abroad.

Currently a postgraduate student, his citizenship bid was strongly supported by several referees, including Dr Melanie Pritchard, the convenor of his Bachelor of Biotechnology honours course last year.

She described him as of sound character and an upstanding citizen of Monash University, adding she was aware he had not done compulsory military service in Singapore.

However, after weighing all the evidence and considering the applicable law, the tribunal rejected his appeal as he had not exhausted all reasonable options to resolve his outstanding issues in Singapore.

"It may be open for him to appeal against the decision of the Singapore authorities to reject his application for a clearance certificate, or to return to Singapore and address the pending offences," wrote Mr Nikolic.

"Obedience to and observance of the law are values that are fundamental to the assessment of character."