Brazilian police have arrested former Finance Minister Guido Mantega as a sweeping corruption investigation struck further at the heart of the Workers Party (PT) that ran the country for 13 years.
Police investigators told a news conference they took Mantega, long a confidant of recently impeached former President Dilma Rousseff and an early member of the PT, into custody at the Albert Einstein Hospital in Sao Paulo. He was there accompanying his wife as she prepared for surgery.
Mantega, 67, was ordered released from custody a few hours later.
The investigators said Mantega in 2012 requested a payment of 5 million reais, about $A3.3 million, at the time, from Brazilian business tycoon Eike Batista, a billionaire who has since lost his fortune, to pay PT campaign debts.
At the time, Batista's shipbuilding unit OSX Brasil SA was discussing an oil platform project with state-led oil company Petroleo Brasileiro SA, known as Petrobras, and loans from state-owned development bank BNDES.
Brazil's longest-serving finance minister of the past 70 years, Mantega in 2012 was also the chairman of Petrobras, the company at the centre of a sprawling political-kickback scheme.
Mantega's lawyer, Jose Roberto Batochio, told reporters late on Thursday that his client never requested money from Batista and said his arrest was "absolutely exaggerated".
A few hours after his arrest, federal Judge Sergio Moro ordered Mantega released from custody.
Moro ruled that Mantega's co-operation with authorities, the fact they had already searched his home, and the fact that Mantega was supporting his wife as she fights cancer all suggested the former minister was unlikely to interfere with the investigation.
His arrest came two days after Moro decided to put former President Luiz Inacio Lula da Silva on trial for allegedly accepting more than $US1 million in bribes from an engineering company in the Petrobras scandal.
