A minister stopped short of describing the incident as a cyber attack but said that it was triggered by those opposed to the proposal, dubbed by some online as the "Great Firewall of Thailand" - a play on China's draconian Internet censorship programme.
The Ministry of Information and Communication Technology's (ICT) website went down for more than two hours last evening after it was "overcrowded" by the number of users, ICT deputy permanent secretary Somsak Khaosuwan, told AFP.
Tens of thousands of people have signed a petition against plans to introduce a single Internet gateway for Thailand to make it easier to monitor the web and block content.
By this afternoon more than 132,000 people had signed a petition on Change.Org calling on the government to abandon the proposal, while the state websites that had crashed appeared to be running but more slowly than usual.
Also Read
At a press conference earlier ICT minister Uttama Savannaya said traffic on the ministry's website exceeded capacity, reaching 100,000 yesterday, causing it to crash.
Internet gateways are the points on a network where a country connects to the worldwide web.
Initially Thailand's Internet flowed through a single gateway owned by the government.
But the sector was deregulated in 2006, allowing dozens of companies to open their own access points - resulting in dramatically increased Internet speeds and Thailand emerging as a regional IT hub.
The junta which seized power in a coup last year has vowed to expand the country's appeal as a hub, unveiling a plan it has dubbed "The Digital Economy". Today, Uttama insisted there would be "no limitation of freedom" under the proposal.
But the minister added that the Thai premier Prayut Chan-O-Cha, who led last year's coup as then army chief, was concerned about some "inappropriate information" accessed by Thais, particularly teenagers.