The Vienna-based UN nuclear watchdog has told Seoul it will send a third team of inspectors on Tuesday for a six-day mission, officials at the science and technology ministry said.

South Korea has been under IAEA scrutiny since its revelations in early September that its scientists secretly enriched a tiny amount of plutonium in 1982 and uranium in 2000.

The IAEA has since sent inspectors to South Korea twice to inspect nuclear facilities, interview scientists and take samples.

"The new team will double-check the results of the previous rounds of investigations and finalize a report to be presented to an IAEA board meeting," a ministry official said.

Seoul has said the experiments, which were conducted without the government's knowledge and were thus undeclared, were scientific research not linked to any weapons programs. It allows full-scale IAEA inspections.

Seoul officials have expressed hope that the IAEA will close the case by reporting in a "fair and balanced" manner to its crucial board meeting on November 25.

The IAEA board will decide whether to refer the case to the UN Security Council, which can impose sanctions on nuclear arms proliferators.

North Korea, citing concern about Seoul's nuclear experiments among other issues, last month refused to attend a proposed new round of multilateral talks on ending its own atomic weapons drive.

But IAEA chief Mohamed ElBaradei has denied any parallels between the two Koreas, citing North Korea's withdrawal from non-proliferation conditions and South Korea's full cooperation with inspectors.

South Korea last week opened the National Nuclear Control Agency, an independent nuclear watchdog, to increase transparency in using nuclear energy for peaceful purposes, the science and technology ministry said.

South Korea has the world's sixth-largest civilian nuclear industry, operating 19 power plants that produce 40 percent of its energy needs.