Two Reuters reporters accused of breaking Myanmar's draconian secrecy law during their reporting of a Rohingya massacre must face trial, a judge said yesterday, in a ruling swiftly decried as a "black day" for press freedom in the country.

Myanmar nationals Wa Lone, 32, and Kyaw Soe Oo, 28, were arrested in December and accused of possessing leaked sensitive material linked to security operations in crisis-hit Rakhine state.

The pair, who have been held in custody for nearly seven months of pre-trial hearings, were both "charged under the state secrets act", Judge Ye Lwin told the court in Yangon, setting a first court date for July 16.

If convicted the two could face up to 14 years in prison under the colonial-era law.

Reuters says the pair are innocent and were simply doing their job by reporting on a massacre of Rohingya Muslims in September, and has urged the court to dismiss the case.

But Judge Ye Lwin decided the prosecution had shown enough proof that the men were "collecting evidence" from state officials to allow the case to proceed to trial.

The legal action against them has been lambasted by rights groups and foreign observers as an assault on media freedom and an effort to stifle reporting on the Rohingya crisis.

Amnesty International, Human Rights Watch and free speech group Article 19 lambasted yesterday's ruling.

"This is a black day for press freedom in Myanmar," said Tirana Hassan, Amnesty International's director of crisis response, labelling the court decision "farcical" and "politically motivated".