Media activists and academics voiced concerns Tuesday over new armbands distributed to reporters covering political gatherings, saying they violate the media's freedom of expression.

Prachyachai Daththuyawatra, the spokesman of the Thai Journalists Association (TJA), said that along with the armbands, preventing the media from compiling news of protests was also viewed as a media rights abuse.

He said the armbands were a similar colour to those worn by police which could stir mistrust among protesters who may see them as a representation of some kind of affiliation between state and media.

The official procedure requires police to contact the TJA beforehand so the association can issue emblems or armbands to reporters who will be stationed at the venues.

However, officers had not worked with the TJA regarding Tuesday's gathering of demonstrators at Thammasat University at Democracy Monument, which made local media feel uneasy, Mr Prachyachai said.

"Media outlets can issue armbands by themselves without relying on police," he added.

The move came after deputy national police chief Srivara Ransibrahmanakul on Monday said members of the media who do not wear armbands issued by the Metropolitan Police Bureau while at an anti-regime rally site will face legal action.

"If this measure is strictly enforced, the media might not agree to follow it because it is impracticable. The measure needs to be more flexible," Mr Prachyachai said.

"At the gathering [Tuesday], even though there were not enough armbands for the media, reporters could still access the area by showing their media identification card to demonstrators. This means the police armbands are useless."

Although police are able to issue regulations in compliance with the Public Gatherings Act, they must not go against the constitution, in which the media's responsibilities are protected under Section 35.

Mr Prachyachai said the media also reported news content in accordance with the association's own code of ethics which prevent it from stirring up conflict and antagonism among the public.

He insisted the media was capable of self-regulation, adding that measures and legal action were pursued against media outlets which caused trouble.

Speaking on the issue, Constitution Drafting Committee (CDC) adviser Jade Donavanik said it was permissible for authorities to devise regulations, but the freedom of expression of both demonstrators and the media must be still preserved under those measures.

"If the media find measures issued by the police bar their operation, it can petition the Administrative Court to abolish the regulation," he added.

In terms of orderliness during the gathering, CDC chairman Meechai Ruchupan said the latest measure was unlikely to go against the charter.

However, he admitted that barring reporters from entering the venues or pursuing legal action against them was an overreaction, adding that the media can oppose the measures.