A Korean student convicted of child pornography offences has asked an Adelaide court to let him travel overseas for military service.

Hui Ung Lee, 19, was given a three-year suspended jail sentence last October.

He admitted he posed as an agent for lingerie company Victoria's Secret and used social media to encourage two girls to send him naked photos of themselves, claiming he could organise modelling contracts for them.

Lee was an athletics coach at Adelaide private schools including Pembroke, Seymour and St Peters at the time of his offending.

The District Court has now been asked to vary the suspended sentence bond to let Lee travel to South Korea for two years to do compulsory military service.

"[I need] probably at least two years because I have got military service," Lee told the hearing.

"As far as I know, the Immigration Department knows about this and agreed I could leave Australia and come back after."

The prosecution said it would be tantamount to Lee failing to serve his sentence but federal authorities needed to be asked if Lee would be allowed back into Australia if he left now.

Judge Paul Cuthbertson said a number of issues needed to be considered.

"I presume he's got an obligation as a citizen of South Korea to perform military duty and I don't know but it might be that if he neglects to appear, he could be committing an offence in South Korea which might put him in jeopardy when he eventually does return to South Korea," he said.

"On the other hand, if he does go back to South Korea perhaps the Australian authorities won't let him back in [to] Australia, him being a convicted person under the law of Australia."

The judge agreed to give the prosecution time to contact federal authorities.

He ordered a further hearing in a fortnight.