Venezuela's former chief prosecutor has resurfaced in Brazil, warning that her life remains in danger and claiming to possess "a lot" of proof of President Nicolas Maduro's corruption.

Speaking at a crime-fighting conference in the capital, Brasilia, Luisa Ortega said on Wednesday: "I have received threats that there may be an attempt against my life and I hold the Venezuelan government responsible if this happens."

Ortega, who fled Venezuela to Colombia with her husband German Ferrer last Friday and flew into Brasilia from Panama late on Tuesday, said Maduro enriched himself in a massive corruption scheme uncovered at Brazilian construction conglomerate Odebrecht.

"I have a lot of proof, concretely in the Odebrecht case, which implicates many high-ranking Venezuelans, starting with the president of the republic," she said. "The rule of law has died [under Maduro]."

For his part, Nicolas Maduro has asked Interpol to put out a "red notice" arrest warrant for Ortega.

He said on Tuesday that Ortega and Ferrer had committed "serious crimes" and should be apprehended. Ferrer is accused by Maduro's government of corruption and extortion.

Al Jazeera's Daniel Schweimler, reporting from neighbouring Argentina's capital Buenos Aires, said it was not clear when Ortega would release any evidence against Maduro, but the president would already be "very nervous".

"The fact that she is coming out with this kind of allegations is going to hit Maduro very hard," he said.

"A number of leaders and senior politicians across the Latin American region have been caught up in the Odebrecht scandal. It has already sent several people to prison."

Schweimler also reported that Ortega and her husband were planning to live in the United States.

READ MORE - Venezuela crisis: All the latest updates

Maduro was elected in 2013 after the death of his mentor, Hugo Chavez.

Venezuela has since descended into a political and financial crisis, exacerbated by a fall in world prices for its oil exports which has left it short of dollars for vital imports.

Clashes between protesters and police this year have left 125 people dead, according to prosecutors.

Maduro's critics accuse him of clinging to power by hijacking state institutions amid shortages of food and medicine. The president accuses protesters of seeking a violent coup and says he is the victim of a US-backed capitalist conspiracy.

Ortega broke ranks with Maduro to become his most high-ranking domestic critic as international pressure on the president mounted.

Last month, Maduro set up a new constitutional body packed with his allies, which a few days later removed Ortega from her post.

Neighbouring Colombia and Brazil have both firmly condemned Maduro's handling of the unrest and economic collapse.

Brazil's prosecutor general said in a statement on Wednesday that he had personally invited Ortega to the country.