The court urged the commission to hear the Liberty Party's complaint and resolve it with "urgent attention", given the "critical" nature of the presidential vote.
"The NEC (National Elections Commission) is stopped and prohibited from conducting the run off election until the complaint filed by the petitions is investigated by the NEC", the Supreme Court ruling said.
The Supreme Court has finally ruled on a request for a writ of prohibition filed by Liberty Party, ordering the National Elections Commission to hold off on holding a runoff election until fraud claims brought by the party are investigated.
Vote scheduled for Tuesday delayed until voter fraud allegation by opposition party, which came third, is resolved.
The court found that the NEC had acted contrary to the law in declaring Weah and Boakai the top two candidates in an October 10 first round election while a question mark over the validity of the votes was pending.
But Liberty Party candidate Charles Brumskine, who came third in the first round on October 10, claims fraud and irregularities tainted the results, leading the Supreme Court to put a temporary stay on preparations.
The run-off, to be contested by former global footballer George Weah for the Coalition for Democratic Change (CDC) against the incumbent Vice President Joseph Boakai for the governing Unity Party, is therefore on ice-and no one knows for how long.
According to a FrontPage Africa report, citing Article 50 of the Constitution, the tenures of outgoing President Ellen Johnson Sirleaf and Vice President Joseph Boakai expires on January 22, 2018.
National Elections Commission lawyer Musa Dean told The Associated Press "the highest court of the land has spoken and we have to abide by the ruling".
Worldwide donors have poured billions of dollars into Liberia since Sirleaf was elected in 2005, and are eager to see completed what will be the country's first democratic transition in seven decades.
George Weah, former soccer player and presidential candidate of Congress for Democratic Change (CDC), is pictured at a church in Monrovia, Liberia October 8, 2017.
The vice president was poised to go public with a weeks-long complaint by his supporters: that Sirleaf backs Weah, not the man who served alongside her in government for 12 years.
Addressing the Supreme Court last week, Brumskine cited "gross irregularities" in the first round.