Venezuela Supreme Court judge Christian Zerpa has fled to the US to protest over President Nicolás Maduro's second term in office.
Last year's election "was not free and competitive", the former Maduro loyalist told a Florida radio station.
And he accused President Maduro of systematically manipulating the affairs of the Supreme Court.
In response, the court said Mr Zerpa was fleeing allegations of sexual harassment.
Opposition parties boycotted the 2018 vote, calling it a sham.
Mr Zerpa had been a crucial ally for Mr Maduro on the court, writing a key legal opinion in 2016 justifying the president's decision to strip congress of its powers.
His ruling Socialist party had lost control of the legislature to the opposition in a landslide vote earlier that year.
But in an interview with Miami broadcaster EVTV on Sunday, Mr Zerpa called the Supreme Court "an appendage of the executive branch", saying the president would tell justices how to rule on certain cases.
He said he had not publicly criticised the 2018 election result to ensure he and his family could safely flee to the US.
Mr Maduro is due to be formally inaugurated to a second term on 10 January.
Fourteen countries recalled their ambassadors from Caracas in protest at the result of the vote last May, and the US imposed fresh economic sanctions on the country.
Before the election even took place, the United States, Canada, the European Union and a dozen Latin American countries said they would not recognise the results.
The opposition had boycotted the poll while the government barred many others from taking part.
Millions of people have fled Venezuela in recent years amid skyrocketing inflation and chronic food shortages.