SEOUL, April 15 (Reuters) - South Korean President Park Geun-hye said she would have zero tolerance for corruption, amid calls for her prime minister to quit over allegations that he took illegal campaign money from a businessman found dead last week in an apparent suicide.

The scandal threatens to weaken Park politically in the third year of a single five-year term and could damage her ruling Saenuri Party, which faces a parliamentary general election next year for control of the 300-seat assembly.

Prime Minister Lee Han-koo faced a second day of intense questions in parliament on Wednesday over whether he took 30 million won ($27,000) in 2013 from businessman Sung Wan-jong, who was found last Thursday hanging by his necktie from a tree while under investigation for fraud and bribery.

Lee denied he took any money from Sung and said he would subject himself to an investigation by prosecutors, rejecting opposition calls for his resignation.

Park said the allegations Sung made before his death must be investigated.

"We must make sure to set straight the fresh allegations that have been raised as a matter of political reform," Park said at a meeting with senior government officials.

"I will not forgive anyone who is responsible for corruption or wrongdoing," she said in her first public comment on the scandal since it erupted last Thursday.

Hours before he was found dead on a mountainside in northern Seoul, Sung said in an interview with a local newspaper that he had given political funds to Park's close aides and to prominent Saenuri Party members of parliament.

Prosecutors found a note on Sung's body making similar accusations, which they said was in his handwriting.

Park's past and current chiefs of staff were named, but all have denied receiving money.

Under a campaign finance law passed in 2004 as the predecessor to the Saenuri Party was battling an earlier bribery scandal before a crucial parliamentary election, political contributions in excess of 100,000 won were made illegal.

Corporations are banned from making political donations under the law, which is aimed at severing ties between the government and businesses looking to secure favours.

($1 = 1,095.3400 won) (Reporting by Jack Kim; Editing by Tony Munroe and Simon Cameron-Moore)