Bangkok (AFP) - Two journalists, including an Australian editor, were ordered Thursday to stand trial in Thailand on defamation charges linked to a Pulitzer Prize-winning article alleging Thai military involvement in people smuggling.

Alan Morison and his Thai colleague Chutima Sidasathian could face up to two years' imprisonment for defamation and five years for breaching the Computer Crimes Act if the court in Phuket finds them guilty.

The charges relate to an article in July last year by the Phuketwan news website, quoting an investigation by Reuters news agency which said some members of the Thai military were involved in trafficking Muslim Rohingya asylum-seekers who had fled Myanmar.

"The court agreed to hear both charges against them," their lawyer Phanom Butakhieo told AFP.

They were released on bail of 100,000 baht ($3,100) each, while Morison was banned from leaving the country, he said, adding that they will return to court on May 26.

"I'm shocked that they are proceeding with the case... it's a big blow," Chutima added after the hearing.

Reuters has not been charged over its reporting -- part of a series honoured with a Pulitzer Prize earlier this week -- and rights groups have accused the Thai navy of trying to muzzle a small media outlet.

"The trial of these two journalists is unjustified and constitutes a dark stain on Thailand's record for respecting media freedom," said Brad Adams, Asia director at New York-based Human Rights Watch.

Media watchdog Reporters Without Borders described the case as "absurd".

"By using the Computer Crimes Act to intimidate journalists, the navy is just making it obvious that it wants to conceal this sensitive information and deter any comments on this humanitarian scandal," said the group's Asia-Pacific head Benjamin Ismail.

Phuketwan is a small but respected English-language news website based in Phuket.

Chutima, who has covered the Rohingya issue in southern Thailand for several years, was also hired by Reuters to work on its award-winning investigation.

A spokeswoman for Reuters said the news agency opposes the "use of criminal laws to sanction the press -- large or small, local or international -- for publication of matters in serious public interest, like the Rohingya stories."

The stateless Rohingya are considered by the UN to be one of the world's most persecuted minorities.

Buddhist-Muslim clashes in 2012 in Myanmar's western state of Rakhine triggered an exodus of Rohingya asylum-seekers by boat.

Rights groups have raised concern about alleged cases of boats being pushed back out to sea after entering Thai waters, as well as the detention of Rohingya by Thailand for illegal entry.

Thailand ranked 130th out of 180 countries in the 2014 Reporters Without Borders press freedom index.

In December the United Nations urged Thailand to drop the charges against the Phuketwan pair, warning of a "chilling effect" on press freedom.