South Korea's Knowledge Economy Minister Hong Suk-woo on Wednesday offered an apology amid a growing controversy over a belated report on the suspension of operation at a nuclear reactor in the southeastern part of the country.

The reactor at the Gori Nuclear Power Plant in Busan, 450 kilometers south of Seoul, saw its operation suspended for 12 minutes without having a backup generator on Feb. 9 during a month- long safety inspection.

But a report of the accident at the Gori-1 reactor was made belatedly on Monday, which prompted the Nuclear Safety and Security Commission to send an inspection team to check the safety of the reactor.

"I apologize to the public for the delay on the report about the suspended operation that took place recently at the Gori-1 reactor," Hong said in a statement.

He said the incident will be thoroughly investigated in accordance with the government's policy pertaining to nuclear power plants, which places top priority on safety issues.

South Korea currently operates 21 commercial nuclear reactors, and the oldest is the Gori-1, which has been in operation since 1978.

The reactor went offline in 2007 when it completed its 30-year life cycle, but was given a 10-year extension.