At least 20,000 demonstrators have taken to the streets of Turkey’s capital Ankara in protest against Prime Minister Recep Tayyip Erdogan’s government, which has been rocked by a vast corruption probe.

At least 20,000 demonstrators have taken to the streets of Turkey's capital Ankara in protest against Prime Minister Recep Tayyip Erdogan's government, which has been rocked by a vast corruption probe.

The government also signalled it may back down on a contentious bid to curb the judges' powers as fierce scuffles erupted in a parliament commission ahead of a second round of debate over the draft bill.

As Erdogan arrived home on Saturday after a week-long tour to Asia, the protesters gathered at Ankara's major Sihhiye Square, chanting "revolution will clean this filth" and "they are thieves".

Some protesters were also handing out fake dollars with Erdogan's photo on them.

The corruption scandal implicating close allies of Erdogan has rattled his government to its core, and poses the biggest challenge to his 11-year rule.

It erupted on December 17, when several public figures, including high-profile businessmen and the sons of three ministers, were detained over allegations of bribery for construction projects as well as illicit money transfers to sanctions-hit Iran.

Forced into a major cabinet reshuffle after the three ministers resigned, the prime minister has responded angrily to the probe, calling it a "dirty plot" to discredit his government.

He repositioned hundreds of police chiefs in a major purge and has moved to curb the powers of the judiciary.

In a different context, the locked-up head of the Kurdistan Workers’ Party (PKK) Abdullah Ocalan has called on the Turkish government to act swiftly to put the peace process on its agenda as soon as possible, warning that the process cannot remain unattended to forever.