The ruling and opposition parties were set to try and issue a joint report Friday on the outcome of their joint confirmation hearing for Prime Minister-nominee Lee Nak-yon, amid opposition criticism of Lee over ethical issues.

A failure to issue a joint report may spell trouble for the ruling Democratic Party and its new liberal President Moon Jae-in, who needs a majority of votes at the 299-seat National Assembly for the appointment of Lee as his new and first prime minister since coming into office May 10.

The rival parties have agreed to try and hold their vote on Lee's appointment Monday at the earliest.

The ruling party controls 120 seats in parliament, while the main opposition Liberty Korea Party and the splinter Bareun Party control 107 seats and 20 seats, respectively.

Lee, a former journalist and lawmaker, was considered a symbol of reconciliation at first for his centrist views and his native hometown in the southwestern part of the nation, considered to have been long neglected from political and economic opportunities.

A two-day confirmation hearing held earlier this week, however, has prompted spicions over many irregularities he and his family may be held accountable for, and that have often led to the oter of top government officials in the past.

Such spicions include a false registration of residence by Lee's wife to be assigned to a school of her choice while working as a public school teacher.

Lee has acknowledged and apologized for many of the allegations.

Many lawmakers from the main opposition party have insisted his and his family's past wrongdoings should disqualify him from the top appointed government post.

Still, many believe parliament will issue the report on Lee's hearing and approve his appointment as the left-leaning opposition People's Party is widely expected to support Moon's pick for prime minister.

The People's Party controls 40 seats in the unicameral parliament. (Yonhap)