Deputy Prime Minister Prawit Wongsuwon said on Sunday that former prime minister Thaksin Shinawatra should not say anything that could foment further conflicts in the country.
Gen Prawit was speaking to reporters at Don Mueang military airport on his return from an official visit to Russia and Belarus on Feb 23-27.
Asked to comment on the invitation by an international organisation for Thaksin to be a guest speaker on the political situation in Thailand in New York next month, Gen Prawit said he was not concerned about this.
"But he should only talk on topics that benefit the country. He should not say anything that could further foment conflict because to do so would be of no use. The country would not be able to move forward. He should love he country, and I believe he does," Gen Prawit said.
Asked whether an election could be held this year instead of next year as proposed by former prime minister Chavalit Yongchaiyudh, Gen Prawit said it had long been declared in the country's road map.
Under the road map, there would be an election in 2017, he added.
Gen Prawit also allayed fears by Gen Chavalit and political observers that the five-year transititional period mentioned by Prime Minister Prayut Chan-o-cha could mean he would remain in this position for another five years. He said this matter would be made clear in the draft charter's provisional clause being worked out by the Constitution Drafting Committee (CDC) under Meechai Ruchupan.
He dismissed speculation that the National Council for Peace and Order (NCPO) would stay on after the election to keep the situation under control.
On Gen Chavalit's call for the NCPO to relinquish its power and hold an election in 2016, Gen Prawit said the former prime minister should take a rest.
"He is very old already and should take a rest. I am very old too and want to rest. I am staying here now only to help the prime minister who has sacrificed for the country. I want to make it clear that I will not be in politics. My physical condition is deteriorating due to the current workload.
"So, whoever is not in a position to speak out should not do so. It's useless to do so. Please convey my message to him (Gen Chavalit) that I want him to rest," Gen Prawit said.
On Gen Chavalit's mention of a terrorist organisation called Black Swan, which is affiliated to the Islamic State (IS), in the South, Gen Prawit said he had never heard of it.
Asked whether he would seek to talk to Gen Chavalit, who was his senior at the Chulachomklao Royal Military Academy, Gen Prawit said that was not necessary.