Several thousand Hungarians protested in Budapest Tuesday against a plan by Prime Minister Viktor Orban's government to nationalize private pension funds from January, a move protestors said amounts to "robbery."

The crowd, estimated at around 2,000 by an AFP photographer, marched to the central bank and the parliament to denounce the plan, which would affect around 60,000 people.

The law was proposed last week by Economy Minster Mihaly Varga, who said it would protect savings and pensions.

Analysts say the scheme would bring an estimated 200 billion forints (650 million euros, $815 million) into the state coffers.

"They want to rob the private property of 60,000 people, next they'll want to rob your toothbrush," speaker Zoltan Buki told the crowd of protesters who chanted "Band of thieves!"

Private sector funds have already lost some 97 percent of their clients after an earlier state takeover of the sector in 2011, a year after Orban came to power.

Holding a placard reading "Robbery is robbery even if it's written into law," 36-year-old IT worker Balazs Horvath told AFP the plan harked back to nationalisations during Hungary's communist era which ended in 1989.

"They've already spent the money they robbed in 2011, now they need the rest," he said.

The demonstration, which passed off peacefully, was the latest in a series of anti-government civil protests organized on social media since October when tens of thousands marched against a proposed tax on Internet usage.

The unusual mass demonstrations forced Orban to scrap that plan, in his first major policy retreat since 2010.

Since then, large protests have also taken place against alleged corruption in Hungary's Tax Authority and against Orban's policies generally in a so-called "Day of Indignation" last week.