PRAGUE (Reuters) - Czech Finance Minister Andrej Babis apologized on Friday after facing calls to quit over comments denying the existence of a World War Two concentration camp for Roma people.

Babis' ANO party leads opinion polls ahead of a national election near the end of 2017 and the billionaire entrepreneur may become prime minister.

He was quoted as telling local residents on Thursday on a campaign stop for regional elections in October that the Lety concentration camp, 80 km (50 miles) south of Prague, had existed only as a labor camp for those avoiding work.

Lety started as a labor camp after the Czechoslovak government ordered its creation in 1939, weeks before Nazi forces occupied the country, for people "living off crime".

But in 1942, German occupiers ordered Roma to be moved into Lety and another camp. Overall, 1,309 people were interned in Lety, according to the website. Of those, 326 died in the camp. About a quarter escaped or were released while the rest were transported to Auschwitz.

Babis was quoted by as saying: "There were times when all Roma worked. What these morons write in newspapers, that Lety was a concentration camp, is a lie, it was a work camp. Whoever did not work, whoosh and he was there."

Roma in the Czech Republic and elsewhere in eastern Europe are often poor and targets of discrimination. Many live in secluded communities with high unemployment.

Prime Minister Bohuslav Sobotka, leader of the center-left Social Democratic party, which ANO rules in coalition with, scolded Babis for crossing the line in harsh comments that showed the tension in the ruling alliance.

"The regional election is getting close and Babis has decided to feed on problems in cohabitation with the Roma," he said his Facebook page.

"There is a very thin line between populism and Nazism. I am afraid the finance minister has now crossed it by these comments," he said, calling on Babis to apologize and brush up on history.

Babis said his comments came after visiting an area where mostly Roma live and he was asking why so many were out of work, as well as why the state has not been able to improve conditions a quarter of a century after Communist rule ended.

"I expressed myself poorly, it was taken out of context ... If I offended someone, then I apologize to everyone," Babis said in an ANO news conference Friday.

Babis said he condemned the Holocaust and concentration camps. Late on Thursday, he also addressed his comments in a Facebook post: "I do not doubt the horrors of Nazism and the World War Two and nobody who knows me could think that."

There is a memorial at the camp site but most of the area is a pig farm, despite long-time efforts by activists to close it.

(Reporting by Jason Hovet and Jan Lopatka; Editing by Alison Williams)