RIO DE JANEIRO -- Embattled Brazilian President was looking to shore up the support of the parties that make up her governing coalition, news reports said Wednesday, a day after the country's largest party decamped in a move that will make it harder for Rousseff to fight impeachment proceedings against her.

Leaders of the Brazilian Democratic Movement Party, known as the PMDB, on Tuesday announced that party members would be immediately leaving their six Cabinet posts, as well as some 600 federal government jobs, but it appeared Wednesday that at least three of the party's Cabinet ministers planned on staying in Rousseff's government. O Estado de S. Paulo daily reported Health Minister Marcelo Castro and Science and Technology Minister Celso Pansera were looking to cut a deal that would allow them to remain in the government, while Agriculture Minister Katia Abreu could sever her ties with the PMDB in order to remain.

Rousseff was said to be planning to use the posts vacated by the PMDB to strengthen her support from the six parties that remain in the governing base, along with her left-leaning Workers' Party.

Rousseff needs to secure at least 172 out of 513 votes in the lower house of Congress in order to halt impeachment proceedings against her over allegations she violated fiscal rules. A vote on matter is expected around mid-April, and without the PMDB's 69 votes, Rousseff's chances of surviving the vote appeared diminished.

Rousseff has seen her popularity plummet amid the worst recession in decades and a sprawling corruption scandal at state-run oil giant Petrobras that has been moving closer to her inner circle. Rousseff, a former chairwoman of Petrobras' board, has not been implicated in the unfolding scandal at the oil company, which prosecutors say is the largest corruption scheme ever uncovered in Brazil.

A new opinion poll released Wednesday suggested just 10 per cent of Brazilians have a favourable opinion of Rousseff. That's just slightly up from the single-digit approval ratings Rousseff faced last year, but still extremely low. The survey, by the Ibope polling agency, has a margin of error of plus or minus 2 percentage points. It was conducted from March 17-20, with 2,002 people interviewed nationwide.

Still, public disgust with politicians reaches far beyond Rousseff. Vice-President Michel Temer, who is first in line to assume the presidency in case of impeachment, has been sullied by accusations he took part in the Petrobras corruption scheme, as have the two other figures in line to succeed Rousseff -- the heads of the lower house and the Senate. All three are with the PMDB and all deny any wrongdoing.

The leak last week of spreadsheets listing payments to nearly 300 politicians representing dozens of parties further inflamed widespread disgust with Brazil's entire political class. The spreadsheets were seized in the Petrobras case from the home of a top executive at one of Brazil's biggest companies and list politicians and their code names alongside monetary figures. Authorities are still investigating whether the sums constituted illicit payouts or were legal campaign donations.