BRASÍLIA – Brazil’s Senate approved on Tuesday a 20-year freeze on government spending billed as the centrepiece of austerity reforms aimed at restoring economic health to the troubled Latin American giant.

The upper house voted 53 to 16 to lock in the spending ceiling.

Center-right President Michel Temer says tough measures are needed to get Brazil’s finances back under control, but his austerity policies have prompted violent protests and were criticized last week by a UN expert as "a historic mistake".

Police were out in force in the capital Brasilia to protect government buildings from demonstrators during the upper house vote, which was wrapped up unexpectedly quickly.

Luis Jorge, a union leader who had come for the protests, expressed anger at the Senate for voting "before we could demonstrate. That makes us very angry."

However, hundreds of people, many with their faces covered, clashed with police later on Tuesday. Security forces fired tear gas to try to disperse the crowd.

A bus was burned during the demonstration, which drew about 2,000 people, police said. The police operation in the capital ended with 100 arrests, officials said.

In Sao Paulo, left-wing protesters attacked the headquarters of FIESP, the country’s main industrial association, before being driven back.

The vote means that the spending cap is now mandated by the constitution, serving as the central plank in Temer’s bid to "transform" the broken economy, which is in deep recession.

However, Temer is rapidly losing political clout as he and many of his senior allies fight to survive a slew of corruption allegations.

Brazilians battered by nearly 12 per cent unemployment and stubbornly high inflation are increasingly angry over the scandals and hostile to the austerity measures.

A poll published on Tuesday showed that 60 per cent of Brazilians oppose the spending ceiling. Only 24 per cent are in favor, according to the Datafolha poll published in the newspaper Folha. — AFP