Prime Minister Prayut Chan-o-cha said the government would move ahead with the 21st round of petroleum concession bidding despite opposition by some groups and lawmakers' vote of disapproval.
"Who's going to take responsibility if we run out of energy over the next six years?" he asked.
On Tuesday, the junta-appointed National Legislative Assembly (NLA) voted 130-79 against the energy reform committee's proposal to proceed with the bidding, with 21 abstentions.
But the premier did not waver.
"It's the duty of the Energy Ministry to ensure security. It doesn't even have to ask for my permission. When the [cabinet] meeting was informed of the bidding, it acknowledged it. When the NLA disagrees, the ministry will check what methods are proposed, which it is doing now," Gen Prayut said.
"The Energy Ministry is handling it. It must move on. For those planning to stage protests, let me be clear. They can't rally. I won't allow it. If they have something to say, they should go to the table. Don't start taking to the streets.
"The ministry explained if a reserve is found, we can still amend regulations on compensation. But today if we cancel the bidding, who can say for sure whether we really have reserves. We have some now and several companies are working on them. But the concessions for 29 of them will end in the next six years so we need to have a backup plan" he said.
Asked what he would do with groups who used to stage energy rallies earlier, Gen Prayut said: "No group could do that again and no forum will be held to brainstorm ideas either. What's done is done. Let's do something else. If you disagree, we acknowledge it, but we need to do what the laws say.
"If we run out of oil over the next six years, will these people take responsibility? If they will, let's sign agreements today," he said.
Earlier on Friday, Energy Minister Narongchai Akrasanee said he would proceed with the bidding and companies could apply on Feb 18 to join the bidding as planned.
"Even though the NLA disagrees with it, we need to honour the commitment and maintain investors' confidence," he said.
The Mineral Fuels Department said production sharing contracts (PSCs), a method championed by the People's Democratic Reform Committee and the majority of the NLA, would take 4-5 years to implement since new laws would have to be enacted. The long delay could jeopardise national energy security.
Energy permanent secretary Areepong Bhoocha-oom said the Thailand III Plus the ministry was using would generate more benefits than the PSC.
Under the Thailand III Plus model, the government will get 80% of revenue after expenses while the ratio is 60% under the PSC regime, he claimed.