The National Council for Peace and Order (NCPO) has ordered a halt to the selection process for core independent organisations until a new constitution is in place.
The order, issued under Section 44 of the interim charter, which grants the prime minister sweeping powers, was published in the Royal Gazette Wednesday.
It bans the selection and appointment processes for Constitutional Court judges, Election Commission members, Ombudsman, members of the National Anti-Corruption Commission and members of the National Human Rights Commission.
According to the order, existing members of those organisations will be allowed to stay until a new selection process is allowed under the new charter.
The referendum for the draft of new charter will take place on Aug 7.
Meanwhile, authorities are hunting those involved in mailing several thousand letters containing allegedly distorted information of the draft charter to households in Chiang Mai, Lampang and Lamphun.
Boontham Prasongwarakit, Chiang Mai's postal office chief, said more than 2,000 letters with allegedly distorted content on the draft charter have been seized.
The letters were posted and destined for delivery to households in San Sai, San Kamphaeng, Mae Rim and Muang districts of the northern province of Chiang Mai, Mr Boontham said.
He said the letters contain content suggesting Thais will lose several rights and welfare benefits under the draft constitution, such as free healthcare, free education, and the monthly allowance of between 600-1,000 baht for the elderly.
Maj Gen Koson Prathumchart, commander of the 33rd Army Circle based in Chiang Mai, said the letters will be handed to the Election Commission to pursue legal action.
In Lampang, more than 2,000 similar letters with alleged distortions of the draft charter which were due for delivery were also found in several mailboxes in the Lampang municipal area on Tuesday.
They were seized for examination.
Some 460 of the same letters were found at post offices in Lamphun.
Maj Gen Kittisak Maenmuen, commander of the 32nd Army Circle, has instructed authorities to keep an eye out for these letters and stop them from reaching residents.
EC chairman Supachai Somcharoen said the EC's Lampang office has filed a complaint asking local police to hunt down and take legal action against those involved in distributing the letters in Lampang.
He says they violate the Referendum Act.
Deputy Prime Minister Prawit Wongsuwon said Wednesday police were looking for people who distributed the letters in Chiang Mai and Lampang.
He also gave assurances preparations have been made to ensure the general election will take place next year even if the draft charter fails to pass in the referendum.
In the event the draft charter prepared by the Constitution Drafting Committee is voted down in the referendum, the interim charter will have to be amended to cover at least four issues: the new writers of the new draft constitution; the way the new draft charter will be drawn up; the timeframe; and the process after the new draft is finished, Mr Wissanu said.