Marines have been accused of killing around 70 civilians during a raid in February 1968, in a case brought to court in Seoul by a Vietnamese woman who survived the massacre.

Seoul's Central District Court last week rejected the government's argument that it was hard to prove South Korean troops were the perpetrators and ruled authorities were accountable.

But defence minister Lee Jong-sup told a parliamentary committee on Friday that his ministry was certain there were "absolutely no massacres committed by our soldiers".

Lee said the ministry "cannot agree" with the verdict and indicated Seoul would appeal.

"Regarding any legal action in the future, we plan to proceed in consultation with related organisations," he said.

The court ruled that victim Nguyen Thi Thanh should be compensated with 30 million won ($23,800), plus interest, for the mass killings in the town of Phong Nhi in Vietnam's central Quang Nam province.

Thanh, 62, who was injured in the raid and lost family including her mother, filed the lawsuit in 2020 seeking compensation from the South Korean government.

Lee said the situation in the Vietnam War was "extremely complex" and it was nearly impossible to verify the woman's claim.

"There were too many cases where those wearing South Korean military uniform were not" South Korean soldiers, the minister told the parliamentary committee.