High-ranking monks of South Korea's largest Buddhist sect, the Jogye Order, resigned en masse on Thursday, a day after prosecutors launched a probe into video footage showing eight of the sect's monks gambling while playing poker.

The investigation was launched after the video footage, which filmed the eight monks with hundreds of millions of won in play at a hotel in southern South Korea on April 23, came under media attention.

"The high-ranking monks tendered their resignation en masse earlier in the day because they need to take responsibility for the incident that should not have taken place," said a senior monk at the Jogye Order.

Ven. Jaseung, head of the Jogye Order, ordered stern punishment for the monks involved and the sect is expected to make an apology to the nation as early as Friday, according to the senior monk who spoke on condition of anonymity.

The gambling accusation is considered the latest incident in a long-running feud between supporters of the Jogye Order's current administration and its opponents, as the footage was secretly recorded by an opponent and then made public.

On Wednesday, one of the opposing group, known by his Buddhist name Seongho, sued his eight fellow monks for gambling and betting "hundreds of millions of won."

In principle, gambling is illegal in South Korea, except for some special areas such as casinos for foreign tourists.

The Joggye Order was rocked in a bloody factional feud in 1999 with hundreds of rival monks brawling over control of the sect,

which claims a membership of more than 15 million people. (Yonhap News)