A South Korean court will weigh Saturday (Jan 18) whether to extend the detention of impeached President Yoon Suk Yeol, after investigators arrested him over a failed martial law bid.

Yoon, who is expected to attend the hearing, threw the nation into chaos on Dec 3 when he attempted to suspend civilian rule, citing the need to combat threats from "anti-state elements".

Soldiers the president directed to storm parliament failed to stop lawmakers from voting down martial law just six hours after his shock announcement.

Yoon was subsequently impeached by parliament and resisted arrest for weeks, holed up in his guarded residence until he was finally detained Wednesday in a dawn raid.

South Korea's first sitting president to be detained, Yoon has refused to cooperate during the initial 48 hours detectives were allowed to hold him.

But the disgraced president remains in custody after investigators requested a new warrant Friday to extend his detention.

A judge at Seoul Western District Court is set to review the request at a 2pm hearing, with her decision expected Saturday night or early Sunday.

Yoon's lawyer Yoon Kab-keun told AFP the president would attend the hearing "with the intention of restoring his honour".

If approved, the new warrant will likely extend Yoon's detention by 20 days, giving prosecutors time to formalise an indictment.

The Corruption Investigation Office (CIO) is probing Yoon for insurrection, a charge that could see him jailed for life or executed if found guilty.

Yoon said Wednesday he had agreed to leave his compound to avoid "bloodshed", but that he did not accept the legality of the investigation.

His supporters have gathered in front of the court since Friday, holding South Korean and American flags and demanding judges dismiss the request to extend the president's detention.

The court closed its entrance on Friday evening to the public, citing safety concerns.

Yoon has refused to answer investigators' questions, with his legal team saying the president explained his position when detained on Wednesday.

The president has also been absent from a parallel probe at the Constitutional Court, which is mulling whether to uphold his impeachment.

If the court rules against Yoon, he will lose the presidency and elections will be called within 60 days.

He did not attend the first two hearings this week, but the trial, which could last months, will continue in his absence.

Although Yoon won the presidential election in 2022, the opposition Democratic Party has a majority in parliament after winning legislative polls last year.

The Democratic Party has celebrated the president's arrest, with a top official calling it "the first step" to restoring constitutional and legal order.

As challenges against the embattled leader mount, parliament passed a bill late Friday to launch a special counsel probe into Yoon over his failed martial law bid.