Yoon was impeached by lawmakers over his disastrous December 3 declaration of martial law, and the court last month held weeks of tense impeachment hearings to determine whether to officially remove him from office.

The wait has only emboldened rival camps to hit the streets in greater numbers every weekend.

On Saturday main streets through central Seoul were filled with protesters for and against Yoon carrying political signs and waving flags despite the cold weather.

"The people are overwhelmed with fatigue and frustration as... the ongoing crises remain unresolved," said Lee Han-sol, 34, who was protesting for Yoon's dismissal.

"The ongoing delays have led to a growing sense of scepticism."

But Yoon supporters, whose members include right-wing YouTubers and religious figures, told AFP his impeachment trial is unlawful.

"The Constitutional Court won't be able to ignore us. Look at us, there so many of us here," said Lee Hye-sook, 58.

The Constitutional Court was given 180 days from the time it took on Yoon's impeachment case to issue a ruling, meaning it has until June to decide his fate.

It has typically issued rulings within weeks for past presidential impeachment cases, but it has taken longer over Yoon's case, without providing a reason.

At least six of the court's eight justices must vote to remove Yoon.

But the wait has also given rise to a surge in speculation, with some suggesting the justices must be experiencing tense disagreements.

The former prosecutor was detained in a dawn raid in January on insurrection charges but was released in early March on procedural grounds. He has remained defiant throughout and blamed a "malicious" opposition.

Yoon also faces a criminal trial on charges of insurrection over the martial law bid, making him the first sitting South Korean president to stand trial in a criminal case.

If the Constitutional Court decides to formally dismiss Yoon, it would trigger elections in 60 days -- which opposition leader Lee Jae-myung is currently frontrunner to win.

This week an appeals court overturned an election law conviction against Lee, potentially clearing the way for him to mount a presidential campaign.

But if it is reinstated on appeal, he will be stripped of his parliamentary seat and barred from running for office for five years, including the next presidential vote.