Constitutional law expert Abdul Aziz Bari has urged the Yang di-Pertuan Agong and the Conference of Rulers to take immediate action following the US Department of Justice's (DOJ) 1MDB-related lawsuits.

Otherwise, he said, the people might heed the advice of former prime minister Dr Mahathir Mohamad, who had yesterday suggested a peaceful rally be held to call for the resignation of Prime Minister Najib Abdul Razak.

"This is the time for the Agong and Conference of Rulers to take immediate action. Don't just release statements anymore.

"If not, what was said by Mahathir, who called on the people to take to the streets to urge for Najib's resignation, will become true," Abdul Aziz told reporters outside of Dang Wangi police district headquarters in Kuala Lumpur today, after he accompanied DAP lawmaker Lim Lip Eng to lodge a police report against 1MDB.

Yesterday, Mahathir had mooted the idea of a peaceful rally after DOJ announced that it had filed civil lawsuits seeking the return of US$1 billion in assets related to what it alleged was stolen 1MDB funds.

Former Bersih chairperson Ambiga Sreenevasan had then said that Bersih was considering the idea.

Abdul Aziz said that it was shameful that it took a foreign body to expose and take action against wrongdoing related to 1MDB.

"How can we expect other countries to clear our backyard?" he asked.

Praising the DOJ and US Federal Bureau of Investigation (FBI) for being so efficient, he said this showed the "sheer incompetence" of the public institutions in Malaysia and they should be ashamed.

Even though 'Malaysian Official 1' is not named in the lawsuit, Abdul Aziz said ultimately 1MDB belongs to the government.

As such, Najib's administration should be held responsible for identifying who Malaysian Official 1 is, he said.

Former Selangor state executive councillor Ronnie Liu also said that the police must investigate the identity of Malaysian Official 1 and reveal who it is.

He also said that while the DOJ has only filed a civil suit in this matter, there are criminal elements throughout the case.