South Korea's presidential office on Wednesday named a new prime minister and finance minister, the highest-level shake-up yet since President Park Geun-hye's administration was rocked by a scandal involving a friend accused of meddling in state affairs.

But the reshuffle quickly provoked anger from opposition parties saying Park was trying to divert attention from the political crisis, which has dragged her approval rating to an all-time low.

The Blue House named Financial Services Commission chairman Yim Jong-yong as finance minister and deputy prime minister. Yim, who will replace incumbent minister Yoo Il-ho, has been well-regarded by policy makers and market participants in his current role.

Kim Byong-joon, a senior presidential secretary during former president Roh Moo-hyun's administration, was named the new prime minister to replace Hwang Kyo-ahn. The prime minister's role in South Korea is largely administrative.

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The late Roh was from a liberal party that rivalled the conservative predecessor to Park's conservative Saenuri Party, and naming Kim appears intended to placate the opposition.

South Korean stocks and the won currency were unmoved by the news.

The shake-up, which also include a new minister of public safety and security, was seen as an effort to soothe public anger over the scandal involving Park's friend, Choi Soon-sil, who is in custody and under investigation by prosecutors.

READ: Friend at centre of South Korea presidential crisis to answer probe

But it did not please the opposition.

"This replacement of the prime minister and finance minister can't be happening without discussing it with the opposition," Park Jie-won, leader of the opposition People's Party, told a party meeting.

"We won't stand by such a move to turn around the current situation with the personnel change."

The prime minister's appointment is subject to parliamentary approval.

Yim, the finance minister nominee, was due to hold a press conference on Wednesday at 0200 GMT, according to his press office.

"The Blue House named Kim as the right person to lead the cabinet for the country's future and to overcome current hardships," presidential spokesman Jung Youn-kuk said.

Neither incumbent Yoo or Hwang has been implicated in the scandal, although Yoo had been under pressure from opposition lawmakers over his close relationship with Park.

A televised apology by Park last week for giving Choi access to draft speeches during the first months of her presidency has done little to deflect demands that Park reveal the full nature of her ties with Choi and whether she enjoyed favours because of her friendship with the president.

Choi arrived at the prosecutors' office on Wednesday morning in handcuffs for a third day of questioning.