Prime Minister Prayut Chan-o-cha on Monday rejected calls for the regime to relax the ban on political activities, saying politicians have failed to improve their behaviour.
Calls for the ban to be lifted intensified after the National Council for Peace and Order (NCPO) last week decided to lift a travel ban imposed on more than 150 individuals shortly after it seized power.
Gen Prayut said he was not considering easing other restrictions, as it could lead to public disorder and threaten the regime's political roadmap.
He also said the lifting of the travel ban had nothing to do with the Aug 7 referendum.
"I'm doing everything I can to maintain peace and order so the roadmap will hold. If they want to derail all this, where does one stand?" said the prime minister.
Asked if the NCPO has detected any signs of political chaos, Gen Prayut said content posted on social media and media interviews indicated certain politicians have not stopped making mischief.
On the subject of politicians criticising the regime from abroad, the prime minister said security authorities would be keeping watch.
Gen Prayut also brushed off the question of whether politicians standing trial for alleged corruption would flee overseas after the travel ban was lifted.
"If they flee, that's not my business. There are legal tools to bring them back, such as asking Interpol for help," he said.
Deputy Prime Minister Prawit Wongsuwon also reiterated the ban on political activities would remain in place to maintain peace and order.
Asked if he was concerned some politicians would campaign against the country from overseas, Gen Prawit said: "Don't ask that. We trust them. We are lifting the ban without any conditions."
He insisted the regime was not under any pressure to lift the travel ban, amid speculation that pressure has mounted on the NCPO following Thailand's appearance at the UN Human Rights Council's Universal Periodic Review Working Group forum in Geneva earlier this month.
Meanwhile, Democrat leader Abhisit Vejjajiva argued the NCPO should remove restrictions to allow political parties to engage in activities that would help them prepare for reforms.
"The NCPO should do it now if it thinks politicians should do something more than contesting in elections. The parties should be able to hold meetings or conduct activities that will allow them to restructure themselves," he said.
"I don't think parties will use party meetings to plan something chaotic. Those who want to cause trouble are likely to resort to secretive means to achieve their ends," he said.
He also urged the government not to use state mechanisms to promote the charter, saying it was almost impossible for those assigned to the campaign to explain only the content of the charter without speaking about its strong points.