South Africa's top court on Friday ruled that Parliament had failed to hold President Jacob Zuma accountable for using public money for private home upgrades, a move that could lead to impeachment proceedings.
Opposition parties had gone to the Constitutional Court to argue that the speaker of Parliament failed to enforce the appropriate processes to censure Zuma over the scandal.
Zuma had failed to abide by recommendations made by the country's anti-corruption watchdog in 2014 over refurbishments at his personal home in the eastern KwaZulu-Natal province that misused $15 million of taxpayers' money.
The scandal came to a dramatic climax when the Constitutional Court last year found the president guilty of violating his oath of office by refusing to pay back the cash.
"We conclude that (National) Assembly did not hold the president to account," said Constitutional Court judge Chris Jafta.
"The failure by the National Assembly to make rules regulating removal of the president... constitutes a violation" of the Constitution, the court said.
It ordered that the National Assembly "must comply" with the Constitution and make rules that could be used for the removal of the president "without delay".
Defeated in court and facing mounting public criticism, Zuma later relented and paid $500,000, a sum set by the treasury following last year's ruling.
In power since 2009, Zuma stepped down last week as president of the ruling African National Congress (ANC) party after a 10-year term marked by numerous damning court judgments against him.
Friday's ruling is expected to pile pressure on the beleaguered leader to resign ahead of the end of his term as state president in 2019.
Zuma was succeeded by his deputy Cyril Ramaphosa in a tightly fought contest in which his former wife Nkosazana Dlamini-Zuma also ran.
Sydney Mufamadi, an ANC stalwart who has known Zuma for decades, said the president would not step aside because he had no "sense of shame" and called on Parliament to act following the judgment.
"This is going to be an acid test of the new leadership of the ANC and Parliament," said Mufamadi, who is now director of the School of Leadership at the University of Johannesburg.
"Parliament has the authority to remove him... not to protect an errant president."
The ANC's deputy secretary general Jessie Duarte said the party had noted the ruling and would "discuss its full implications" when the party's decision-making National Executive Committee meets on January 10.
One of the opposition parties that took the matter to court, Congress of the People, said the ruling had left Zuma exposed and put the ANC under pressure to act against him.
"He has reached a point at which he is like Saddam Hussein in a hole and there is no other chamber to go except to come out. He's got to come out now," said COPE leader Mosiuoa Lekota.
In a statement the National Assembly said it had "already initiated a process, as part of its overhaul of rules" to put in place a procedure for removing a sitting president.
Ralph Mathekga, a political analyst and author of the book "When Zuma Goes", said the judgment would strengthen the position of those seeking to remove Zuma.
"Zuma is on his way out, the only difference is how ANC members will negotiate with him. It's going to take negotiations with Zuma so that he can leave office," Mathekga said.
The main opposition Democratic Alliance party has said it will seek to have its parliamentary motion of impeachment against Zuma "re-tabled" as soon as possible.