Sudanese authorities on Tuesday filed new charges against ousted leader Omar al-Bashir and some of his aides for "plotting" the 1989 coup that brought him to power, the country's protest movement said.

Bashir, who was a brigadier at the time, seized power in an Islamist-backed coup that toppled the then elected government of prime minister Sadiq al-Mahdi.

But Bashir himself was ousted by the army in April after months of nationwide protests against his iron-fisted rule of three decades.

He has already been jailed since, but on Tuesday authorities filed a separate case against him and several of his aides for the 1989 coup.

"Arrest warrants have been issued against all military and civilian members who plotted and carried out the 1989 coup," the legal committee of the protest movement Forces of Freedom and Change (FFC) said in a statement.

It said arrest warrants and travel bans were issued against Bashir, and other top figures of his regime, such as Nafa Ali Nafa, Ali Osman Taha and Ibrahim al-Sanousi.

The authorities have also issued arrest warrant against Ali al-Haj, a senior leader from the Islamist Popular Congress Party, which was an ally of Bashir's government.

Like Bashir, Nafa and Taha are already in prison, while Sanousi and Haj are still free.

The FFC said the prosecutors informed them of the new arrest warrants and travel ban against Bashir and others during a meeting earlier on Tuesday.

A source in the prosecutor's office confirmed to AFP that new arrest warrants had been issued against Bashir and his aides.

The Sudanese Professionals Association, which is part of the umbrella protest movement and initially spearheaded the campaign against Bashir, also posted the FFC statement on Twitter.

If found guilty, the accused could face death penalty or life imprisonment under Sudanese law.

Bashir is also wanted by The Hague-based International Criminal Court for genocide, war crimes and crimes against humanity for his alleged role in the war in Darfur.

He is currently on trial in a Sudanese court for illegally acquiring and using foreign funds.

Sudan is now ruled by a joint civilian and military sovereign council, which is tasked with overseeing the country's transition to a civilian rule as demanded by the protest movement.