SEOUL (AFP, REUTERS) - South Korean officials summoned Volkswagen representatives to discuss emissions tests after the German auto giant was accused of cheating on US air pollution standards, the Environment Ministry said on Tuesday (Sept 22).

"We've called in Volkswagen representatives and engineers to the ministry for a meeting on Wednesday afternoon," Deputy Director Park Pan-Kyu of the ministry told AFP.

"We will start conducting tests no later than next month and announce tests results by the end of November," he said.

Mr Park said it was too early to say what kind of punitive measures the government could take against the firm until the test results become available.

The US Environmental Protection Agency (EPA) said the Volkswagen had been fitting diesel vehicles in the US with software that turns on full pollution controls only when the car is undergoing official emissions testing.

As a result, the cars emit greater-than-allowed quantities of pollution linked to smog and various health problems.

The alleged violations affect nearly half a million vehicles in the United States and could result in fines totalling as much as US$18 billion (S$25.4 billion).

Of the five models equipped with test-cheating software in the United States, four have been imported to South Korea - the Golf, Audi A3, Jetta and Beetle.

About 59,000 of those models are on the road in South Korea now, Park said.

Heads are certain to roll at Volkswagen once it becomes clear who at the German carmaker was responsible for the falsification of emissions tests of diesel-powered vehicles in the United States, a German politician and VW supervisory board member said on Tuesday.

"I am sure that there will be personnel consequences in the end, there is no question about it," the German state of Lower Saxony's Economy Minister Olaf Lies told German radio station Deutschlandfunk in an interview. But he said a thorough investigation would first have to identify the person or people who were involved in the issue.

VW chief executive Martin Winterkorn issued an apology and said the group had ordered an external investigation into the matter, adding that it took the EPA findings "very seriously."

The news had sent the company's stock down by nearly 20 per cent on Monday.