WASHINGTON (AFP) - Myanmar should repeal laws and develop a code of conduct for journalists to ensure further progress amid an opening in the country's long-closed media, Reporters Without Borders said.

The Paris-based media rights group was allowed to visit Myanmar for the first time as the nation formerly known as Burma undertakes major reforms, which have included an end to direct censorship by the government.

In a report, Reporters Without Borders said that no journalists or bloggers remained in Myanmar's prisons and that the reforms were initially seen as a "breath of fresh air" for private media.

"Confident that they could be a lot more outspoken, they tried to publish articles critical of the authorities but quickly discovered that the government's red lines had not retreated as much as they had imagined," said the report, released early Thursday in Paris.

Authorities in August issued "guidelines" to journalists, such as not writing critically about the government. Reporters Without Borders said that Myo Mying Maung, director of the once-feared censorship bureau, told the group that the guidelines were "just suggestions," despite journalists' misgivings.

Reporters Without Borders called for Myanmar's government to affirm its commitment to freedom of information by moving to repeal "repressive" media laws that remain on the books and to dismantle the information ministry.

The group also called for Myanmar to overhaul state-owned media and provide access to government institutions for all journalists.

Myanmar's new Press Council should draft laws and a code of conduct that protect reporters and conform to international standards, while journalists should take care to cover the country's diverse ethnic groups, the report said.

President Thein Sein launched a string of reforms after taking office as a nominal civilian in 2011, including allowing once-detained opposition icon Aung San Suu Kyi to take a seat in parliament.