Amid calls for impeachment of Brazil President Dilma Rousseff, her biggest ally in Parliament Brazilian Democratic Movement Party (PMDB) is set to vote Tuesday to leave the coalition with her Workers' Party. With the PMDB's exit, Rousseff's impeachment is expected to become easier, paving way for PMDB leader and Vice President Michel Temer to assume the role of the president.

The PMDB, in its top level meeting Tuesday, is expected to vote in favour of the exit from the alliance as Rousseff faces corruption charges. She is also accused of shielding her mentor and former President Luiz Inacio Lula da Silva by appointing him chief of staff. Silva faces investigation in the state oil company Petrobras graft case, which a lower court is overseeing. The PMDB is also under investigation for the case. Brazil, in December 2015, also lost its investment-grade rating amid a widening fiscal deficit.

PMDB member and Tourism Minister Henrique Eduardo Alves was quoted as saying by Reuters that "Dialogue, I regret to say, has been exhausted," while handing over his resignation Monday.

Workers' Party founder Silva, however, said Monday that Rousseff can still survive the calls for her impeachment. The Associated Press quoted him as saying that he would talk to Temer about Rousseff keeping her job despite her growing unpopularity.

"No one likes to support an administration that is not doing well with public opinion," Silva was quoted as saying by AP. "But we need to keep talking to" the Democratic Movement, he added.

Polling institute Datafolha's poll pegged demand for Rousseff's impeachment at 68 percent, however, only 11 percent believed Temer to be better, according to AP.

"An impeachment without legal basis is a coup," Silva, quoted by AP, reiterated Rousseff's statement from last week. "These are excuses and fake arguments to shorten the term of the person who won the elections."

Speaker of the lower house of Congress, Eduardo Cunha, had agreed in December 2015 to begin impeachment proceedings against Rousseff, who is on her second term as president, after she was found to have tampered with financial books to cover the actual fiscal deficit, according to the Economist.

Recently, huge rallies were held by pro and anti-government supporters across the country, following which Silva said that he was joining the government as Brazil was facing the worst recession in years and needed to restart growth.