Brasilia: Brazilian President Dilma Rousseff's looming suspension from office was back on track on Tuesday after the speaker of the lower house of Congress withdrew his controversial decision to annul an impeachment vote against her. The Senate will vote on Wednesday whether to put Rousseff on trial for breaking budget laws. If, as is widely expected, a simple majority agrees to hold the trial, she will be automatically suspended from office for up to six months. Vice President Michel Temer would take over as president, and if Rousseff were convicted and removed definitively, he would stay in the post until elections in 2018. As the prospect grew of Rousseff's ouster and a potential end to 13 years of rule by her leftist Workers Party (PT), anti-impeachment protesters blocked roads with burning tires in demonstrations in Sao Paulo, the capital Brasilia and other cities, snarling morning traffic. The PT and labour unions called for a national strike to resist what they call a "coup" against democracy. Speaker Waldir Maranhao's surprise decision on Monday to annul the lower house's April vote threw Brazilian markets into disarray and threatened to drag out a painful political crisis with a constitutional standoff that could have ended up at the Supreme Court. Brazil's currency, the real, strengthened 1 per cent early on Tuesday after the speaker's reversal - a reflection of investor hopes that a more market-friendly government will soon take over the recession-hit country under Temer, who is forming a cabinet with pro-business figures. In a statement to the Senate, Maranhao did not cite any reason for backtracking on his decision to annul due to "procedural flaws" the lower house's April 17 vote. The vote had overwhelmingly recommended that the Senate try Rousseff. Maranhao, a little known politician before taking over last week after the removal of Eduardo Cunha for obstruction of a corruption investigation, faces expulsion from his center-right Progressive Party, which supports Rousseff's impeachment. Senate President Renan Calheiros said Monday that Maranhao was "playing with democracy" and vowed the Senate would press ahead with Wednesday's vote. It is expected to take place at about 8pm (2300 GMT) at the end of an all-day session of speeches. Rousseff's opponents have more than the 41 votes needed to launch her trial in the upper chamber, and they are confident they can muster two-thirds of the 81 senators, or 54, to unseat the unpopular president at the end of a trial that can last up to six months. If she loses Wednesday's vote, Rousseff will be served notice by the Senate on Thursday, at which point the suspended president must vacate the presidential palace. She can continue to live in the presidential residence during the trial. Temer would step in as interim president as soon as she is given notice. The impeachment process comes as Brazil is mired in its worst recession since the 1930s and shaken by the country's biggest ever corruption scandal - which have paralyzed Rousseff's second-term administration. Rousseff has steadfastly denied committing any impeachable crime and has vowed to fight impeachment by all means legally possible. She has dismissed calls for her resignation. The impeachment process is unfolding as investigators pursue a separate, long-running probe into a vast kickback scheme at state-run oil company Petrobras. "Operation Carwash" has ensnared dozens of top politicians and jailed chief executives from Brazil's biggest construction firms for paying billions in bribes to lock up bloated building contracts. The political crisis has hit at a time when Brazil would want to be shining on the world stage, as it prepares to host the Olympic Games in Rio de Janeiro in August.