A plan to replace martial law with sweeping new powers for Prime Minister Prayut Chan-o-cha has prompted fears it will promote human rights abuses.

Critics of the plan are concerned that Gen Prayut will use a new order issued under Section 44 of the interim charter to give himself absolute power over executive, legislative and judicial decisions.

Yodpol Thepsitthar, a law lecturer at Naresuan University, described Section 44 as a "dictatorial law" and said it would be no better than leaving martial law in place.

Section 44 is modelled on Section 17 of the 1959 constitution, brought in by the regime of Field Marshal Sarit Thanarat. Mr Yodpol said the regime used its power to execute about 10 people tied to drug cases.

He said while martial law granted military authorities power over civil authorities in security operations, Section 44 would grant absolute power to the junta chief.

Gen Prayut would have the power to order the arrest, imprisonment or execution of any individual without any criminal investigation process, Mr Yodpol said.

He said the prime minister had exercised his executive powers under Section 44 once before, but only to issue an order allowing executives and members of local bodies to continue working.

“That was a use of administrative power which doesn’t cause any problem. But we don’t know how far he will go,” Mr Yodpol said.

Gen Prayut suggested on Friday that martial law, which has been in effect since May 20 last year, would be lifted and replaced by a new order issued under Section 44, although did not specify when this would occur.

Justice Minister Paiboon Koomchaya said the prime minister would be the one to issue the orders under Section 44, and he did not know what they would contain.

Gen Prayut’s remarks followed growing calls both here and abroad to lift martial law, which grants military authorities full power of search and seizure, among other powers, and protects them from legal action.

Chiang Mai University law associate professor Somchai Preechasilapakul said Section 44 essentially provided absolute power to the prime minister.

He said Gen Prayut would be able to overrule judicial and legislative authority by penalising anyone without having to seek court endorsement.

Ramkhamhaeng University law associate professor Sukhum Nualsakul said the new powers could allow for any individual to be detained at any time and for any duration. Mr Sukhum believed the government was bowing to pressure to revoke martial law purely for the sake of tourism and investment.

Pairoj Polpetch, a member of the Law Reform Committee, called on the prime minister not to invoke Section 44, saying it would do more harm than good. “The rights of the people can easily be violated if Section 44 is enforced," Mr Pairoj said.

Pheu Thai Party member Phongthep Thepkanchana said invoking the section was against the rule of law and would pose a greater threat to human rights than martial law.

He said the government would only be able to “fool” the international community for a short while after martial law is lifted.

Mr Phongthep said that Gen Prayut had so far refrained from using his powers the section in a way that threatens human rights and civil liberties.

“I don’t know how or to what extent Section 44 will be enforced. We’ll have to wait and see. But there will be repercussions,” he said.

United Front for Democracy against Dictatorship chairman Jatuporn Prompan said the powers under Section 44 were not bound by any fixed legal or constitutional rules, and so there was no guarantee of how the junta chief will exercise them.

"We know what martial law is and what it contains. But for Section 44, it depends solely on the judgement and emotions of the person who wields the power," he said.

Thaworn Senneam, a leading member of the People’s Democratic Reform Committee, which led the street protests before last year's coup, said he supported the enforcement of Section 44. But he called on Gen Prayut to control his temper and use the power carefully.