Speaking at a regular government press conference on Wednesday, Deputy Minister of Planning and Investment Nguyen Duc Trung reasserted that upon being tasked with selecting businesspersons to accompany National Assembly (NA) Chairwoman Nguyen Thi Kim Ngan on the trip, the ministry had worked with the police and functional forces to inspect the backgrounds of all participants.

The fact that nine of the businesspersons overstayed was therefore "unforeseen" and "very unfortunate," and it was the first time such an incident with such serious consequences had occurred, he said.

Trung said his ministry has found itself "responsible" and has held meetings to learn from the experience, as well as to review and tighten procedures for selecting businesses accompanying officials.

The ministry will punish officials found to have made violations during the selection process should any such violation be detected, he added.

The identities of the nine overstaying businesspersons have yet to be revealed as Vietnamese and South Korean authorities are still investigating the case.

Trung also defended the policy to help businesses participate in government and party officials' sideline activities overseas as "completely correct" as it provides regular opportunities for Vietnamese businesses to carry out investments and do business with foreign firms.

On Wednesday last week, head of the NA Office, Nguyen Hanh Phuc, had confirmed that nine Vietnamese had illegally stayed on in South Korea after going there on a chartered jet with Ngan, who'd been invited to make a speech at the Vietnam-South Korea Investment and Trade Forum as part of her official visit to South Korea last December.

Phuc made the statement after South Korean media reported on the matter.

The nine were not part of the Vietnam National Assembly's diplomatic group and were not granted diplomatic visas, he said.

Two of them have since been deported, and Vietnamese police and South Korean authorities are trying to find and deport the remaining seven, who would be dealt with in accordance with the law upon their capture.