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.