South Korea on Friday jailed six nuclear power engineers and suppliers linked to a major corruption scandal that stoked public concern over safety standards.

Two engineers with state-run Korea Hydro and Nuclear Power (KHNP) were handed prison terms ranging from 14 months to two years for taking bribes from suppliers who used forged safety certificates.

Four suppliers were given jail sentences ranging from eight to 14 months by the court in the southern city of Gwangju. Three other defendants -- one engineer and two suppliers -- received suspended sentences.

All parts for South Korea's 23 nuclear reactors, which meet more than 35 percent of national electricity needs, require quality and safety warranties from designated organisations.

But suppliers faked warranties covering thousands of items used mostly in a major nuclear power complex in Yeonggwang on the southwest coast, according to government officials.

"This case revealed widespread insensitivity to safety at our nuclear power plants," the court said in a statement.

The trial followed a series of malfunctions, forced shutdowns and corruption scandals that undermined public confidence already shaken by the 2011 Fukushima nuclear disaster in Japan.

In May last year, five senior KHNP officials were charged with trying to cover up a potentially dangerous power failure at the country's oldest Gori-1 reactor.

Later in the year, the government shut down two reactors at Yeonggwang to replace components. A third reactor was taken offline at Yeonggwang when cracks were found in control rod tubes.

The shutdowns in Yeonggwang prompted authorities to inspect all reactors nationwide, although KHNP officials insisted there had never been any threat of a radiation leak.

The government has vowed to push ahead with its nuclear power programme, and plans to build an additional 16 reactors by 2030.