Prime Minister Prayut Chan-o-cha on Tuesday denied that the military regime was conspiring to delay next February's election via potential plans to submit a poll-related bill to the Constitutional Court for a ruling on its validity.

The bill on the election of MPs may be forwarded to the charter court for the ruling before it is submitted for royal endorsement, Gen Prayut said.

The premier earlier promised the poll would take place next February, a claim critics have taken with a pinch of salt as it was originally scheduled to be held in 2015.

The final two organic bills facilitating the return to democracy -- one on electing MPs and another on the selection of senators -- sailed through the National Legislative Assembly (NLA) on March 8.

That same body on March 19 decided to forward the latter bill to the charter court to rule on its constitutionality as requested by the Constitution Drafting Committee (CDC). However, it ignored a similar request for the MP bill.

The assembly forwarded the bill to the prime minister so he could decide the next step.

"I don't want to submit it for royal endorsement as long as there are still disputes," he said.

The situation requires careful consideration in order to avoid further problems, he went on. He has asked legal officials to look closely at the bill and determine whether the charter court should be asked to vet it. He has until April 12 to decide whether to petition the court.

After receiving the bill from the NLA, the prime minister is obligated to submit it to the palace for royal endorsement within 25 days.

Gen Prayuth, however, insisted the roadmap should not be changed as the vetting proceedings are expected to be quick.

The bill contains two controversial points that the CDC has disputed.

One concerns a clause that allows helping disabled people cast their vote, something the charter drafters said could compromise the secret ballot.

Another involves the clause that prohibits people who fail to vote in national elections without good reason from being appointed as political office holders, something that the CDC considers a step too far.

"The government will solve the problem first. I can confirm this will not affect the roadmap," Gen Prayuth said. "We are considering [petitioning the court]. We still have time. But as I've said, whether or not we do this must be decided in consideration of the roadmap."

He insisted there was no conspiracy to delay the return to democracy. "I'm not interested in dragging things out," he said but added that it was important to make sure the bills would not spark legal disputes that could derail social stability.

Meanwhile, Deputy Prime Minister Prawit Wongsuwon said if the charter court rules against any of the two bills, the legislation would be dropped and the drafting process would have to start anew.

The prospect of the petition has drawn flak from the Pheu Thai Party.

Pheu Thai member Chusak Sirinil said it is not clear how long the court would need to deliberate the bill but the timing of the election would come under threat.

"I don't understand what their intention is," he said. "Are they just trying to buy time? Whatever the reason, this is causing people to lose confidence [that the premier will keep his word regarding the February date]. This does suggest that members of a certain group intend to cause problems with the legislation. If they had wanted to write a charter-aligned bill, they could have already done so."

Pro-election activists are putting pressure on the military to stop supporting the NCPO and resign from the council. They demanded the NCPO be dissolved and the government remain only in a caretaker role.

The group rallied in front of the Royal Thai Army Headquarters on Ratchadamnoen Avenue on Saturday. They vowed to stage a bigger and longer rally in May unless their demands are met.