Thai authorities are reported to have ordered internet providers to block the Telegram messaging app, which has been used by anti-government protesters.
A leaked document outlining the plans was shared on social media.
Police also threatened to shut four news outlets for violating a decree issued last week to end the rallies.
Pro-democracy activists have held months of protests calling for the resignation of the prime minister and curbs on the powers of the monarchy.
Members of the student-led movement have gathered in defiance of an order banning protests and want Prime Minister Prayuth Chan-ocha – a former army chief who seized power in a 2014 coup – to resign.
Their demands for reform have since grown to include questioning the role of the monarchy, an institution long seen as sacred in Thailand.
Authorities have failed to curb the rallies since they issued an emergency order on Thursday, with protesters still gathering daily, largely peacefully, in Bangkok and other parts of the country.
At least 80 people have been arrested since Tuesday. Those detained risk long sentences if they are found to have breached Thailand’s strict lese majeste laws, which ban criticism of the monarchy. Anyone found breaking the law could be jailed for up to 15 years.
The government’s plan to block Telegram was reported by local media on Monday after a document marked “very confidential” was leaked and shared widely on social media. Telegram is a popular secure messaging app that has been used by activists to organise protests at short notice.
he document – apparently produced by Thailand’s digital economy ministry, which has the power to censor the internet in Thailand – was sent to the National Broadcasting and Telecommunications Commission
“The Ministry of Digital Economy and Society is seeking your co-operation to inform the Internet Service Providers and all mobile network operators to suspend the use of Telegram app,” it said.
Separately, police told reporters they had instructed the digital ministry to restrict Free Youth’s group on Telegram. The group has played a key role in organising protests in recent months.
It is unclear how effective the order will be in curtailing the democracy movement.
In a separate order, Thai police said they were investigating four well-known news organisations over their live-reporting of the protests. Prachatai, Voice TV, The Reporters and The Standard have reported extensively from the protest sites.