A lawyers group has expressed shock at Anwar Ibrahim's threat of jail against anyone commenting on a recent revelation by Bloomberg that the government was considering a second casino in Johor, questioning what it called a pattern of invoking the royal institution to justify the use of draconian laws against critics.

Lawyers for Liberty (LFL), which has repeatedly condemned the arrests of government critics, said Anwar had tried to justify the action during a speech to civil servants yesterday by saying it was to safeguard the royal institution, when the criticism was directed against his own alleged involvement in the casino talks.

"The PM cannot hide behind the royal institution in order to shut down public criticism or comment against himself," said LFL director Zaid Malek.

"We also note that there is now a pattern of conduct where the PM invokes the royal institution as an excuse to wield oppressive laws such as the Sedition Act. This backdoor way of justifying the denial of freedom of speech and the use of oppressive laws must stop."

Zaid also said that Anwar was going after the wrong parties in clearing his name.

"Anwar or the government have taken no steps to ask for the casino story to be retracted or to take any form of legal action against Bloomberg or other news sites regarding the claims, and the news remains available for anyone to access to online," he said.

"Having chosen not to do this, why instead target the Malaysian public who comment on the news or express concern or criticism in relation to it?"

He also said the prime minister's threat to jail his critics was "unlawful, unprecedented and chilling".

"It is not the job or power of the prime minister to threaten arrest or imprisonment against the public. Neither is it his job to decide whether anyone has committed any crime," he said, adding that the prime minister "has no business usurping" the role of the police and judiciary.

Zaid said it was shocking that such a threat had come from "a leader once seen as a leading advocate for reform in Malaysia".

"By any standards, this is a lurch towards authoritarian rule."

Yesterday, Anwar slammed those who urged him to come clean on the report by financial news Bloomberg last week as "criminals", claiming they had accused him of giving approval for the alleged casino plan.

"These people should be sent to my previous cell in Sungai Buloh," said Anwar, referring to Sungai Buloh Prison where he was once imprisoned for sodomy.

The remarks followed a series of arrests under the Sedition Act for commenting on the Bloomberg report, which set off a string of debates on social media.

Anwar has also come under pressure to take legal action against Bloomberg, with critics saying that mere denials are not enough to clear his name.

Bloomberg neither removed nor retracted its article so far.

In the report, it said Anwar had met with tycoons Vincent Tan of Berjaya and Lim Kok Thay of Genting, as well as representatives of Yang di-Pertuan Agong Sultan Ibrahim Sultan Iskandar, to discuss plans to open a casino in Forest City.

"Anwar, senior government officials and the businessmen had lunch and meetings on the possibility of granting what would only be Malaysia’s second-ever casino licence," the report said, adding that the talks were "preliminary".

Anwar denied the report, calling it a lie, but stopped short of saying whether he would seek a retraction from the US-based media group.

Instead, he called on the parties named in the article to "take the necessary action".

This was followed by denials from Berjaya and Genting Bhd, two companies involved in Malaysia's gambling industry.

Zaid said that Bloomberg was a reputable news organisation, like The Wall Street Journal whose exposure of the 1MDB scandal involving Najib Razak sparked outrage among Anwar and other Pakatan Harapan politicians.

"Under Najib, police action was taken against those speaking out on the issue, just as Anwar is threatening jail to all and sundry who talk about the casino issue," he added.

Zaid said anyone could discuss the issue as it was their constitutional right under Article 10, adding that this was the same provision "once much relied on by Anwar and his colleagues in PH" when they faced action from the authorities at the time.

"Now, they appear to regard it as a nuisance."