Parliament's failure to reject the National Security Council (NSC) Act will be remembered as a "dark and sinister" chapter in Malaysian history, said the Institute for Democracy and Economic Affairs (Ideas).

Ideas chief executive Wan Saiful Wan Jan said it was clear the Conference of Rulers'  concerns and issues about the NSC Act remain unaddressed.

"The fact that it has had no express royal assent, despite now entering into law, should clearly communicate to the Malaysian people and the legislators in the Dewan Rakyat and Dewan Negara that there are concerns and issues from the rulers which remain unaddressed or ignored.

"We must break our silence and ask why the government was insistent in pushing this through, despite the lack of approval from the Yang di-Pertuan Agong," Wan Saiful (photo) said in a statement today.

He reminded the people that the NSC Act, which allows for "extensive curtailing and further restrictions on constitutionally guaranteed civil liberties and freedoms" had very little legislative scrutiny and almost no public consultation.

"It is at times like this that one is reminded of the wise words of historian and politician Lord Acton, that power tends to corrupt, and absolute power corrupts absolutely. 

"The prime minister now possesses at his disposal a concentration and breadth of power that has no historical precedence in Malaysia. We are truly in uncharted waters," he said.

The "bitter" experiences of other countries should have been good examples of what would happen when authoritarian rule becomes a reality, regardless of good intentions, Wan Saiful said.

"Let us hope we do not suffer their fate," he added.

The NSC Bill 2015 has been gazetted into law, without royal assent, despite calls by the Conference of Rulers for the legislation to be refined.

According to the gazette published on Tuesday, the bill was declared as assented on Feb 18, 2016, under Clause 4(a) of Article 66 of the Federal Constitution.

Clause 4(a) states that a bill becomes law 30 days after it is presented to the Yang di-Pertuan Agong, even if the Agong does not assent.

The NSC Act, among others, allows the imposition of emergency-like conditions in security areas declared by the National Security Council (NSC), which is headed by the prime minister.

The government has been criticised for trying to impose dictator-like conditions in Malaysia, but Najib said such a law is required to deal with terrorism.