Chung Mong-joon, a seven-term lawmaker and controlling shareholder of the world's largest shipbuilder Hyundai Heavy Industries, is expected to announce his presidential bid soon, local media reported Saturday.

Chung, the son of late Hyundai founder Chung Ju-Young, will compete in the conservative ruling Saenuri Party's primary that will nominate a candidate for the December presidential poll.

He will be the second Saenuri heavyweight to toss his hat into the ring, after Gyeonggi Governor Kim Moon-soo announced his candidacy for the party primary.

Lee Jae-oh, a five-term lawmaker with close ties to President Lee Myung-bak, is also expected to try his luck in the primary.

Observers say an unlikely alliance could be formed among the three lawmakers as they seek to fight off interim Saenuri leader Park Geun-hye, considered the strongest presidential hopeful on the conservative ticket.

Chung, among the country's richest politicians, donated 200 billion won (176.8 million U.S. dollars) last year to a charity organization in an apparent attempt to demonstrate social responsibility of chaebol, the family-controlled conglomerates.

Critics saw the donation as a way of raising his national profile in the face of an anti-chaebol sentiment brewing among South Koreans disgruntled with the lackluster economy.

President Lee's five-year term ends early next year.