President Moon Jae-in on Friday asked the incumbent Cabinet members to help run his new administration at least until he finds their replacements.

The president's request to the ministers appointed by his ousted predecessor Park Geun-hye came at a lunch at the presidential office Cheong Wa Dae.

"The president wished to encourage the ministers and also listen to any advice they had to offer," a Cheong Wa Dae official said on the condition of anonymity.

Friday's lunch involved all 16 government ministers.

However, it did not and should not suggest the president planned to keep the ministers for good, the official noted.

"We are working to find new ministers, but frankly, it may take a month or even two," he said.

Also present at the lunch were Finance Minister Yoo Il-ho and Foreign Minister Yun Byung-se, both of whom have already been asked to step down after the president named his nominees to replace them.

Moon noted all incumbent ministers will have to go eventually, but said their cooperation was required, at least for now.

"A cabinet shake-up is unavoidable, but I ask you to think of yourselves as the first cabinet of the Moon Jae-in administration and work with us," he was quoted as saying.

The president also asked the incumbent ministers to help him at least for the sake of their own country.

"Regardless of how we evaluate the entire Park Geun-hye administration, it is important to maintain continuity in the policy efforts of each government ministry," he said, according to his spokesman Park Soo-hyun.

"Political powers (governments) expire, but our homeland is eternal," Moon added.

New Cabinet members are required to undergo a confirmation hearing by a National Assembly committee, though their appointment does not require the parliament's approval.

President Moon was inaugurated on May 10, one day after the country held a rare presidential by-election to fill the vacancy in its top elected office caused by the ouster of Park.

The former conservative president was removed from office on March 10 by a Constitutional Court ruling that upheld her late 2016 parliamentary impeachment over a series of corruption allegations.

Park is currently facing a criminal trial over corruption charges. (Yonhap)