Prime Minister and Leader of the Jamaica Labour Party Andrew Holness leaves a polling station after voting during the Jamaican General Elections in Kingston, Dec 29, 2011. [Photo/Agencies]

KINGSTON - Jamaica's ruling party appeared headed for defeat in national elections on Thursday, as the Caribbean country's leading opposition party capitalized on voter discontent over growing economic woes.

Preliminary results showed the governing Jamaica Labour Party winning just 21 of the 63 parliamentary seats at stake in the national election.

With about 50 percent of ballots counted, according to results from the national electoral office posted on the website of the Jamaica Observer newspaper, the opposition People's National Party looked set to win 42 seats.

If that trend holds up, and is confirmed later by the Electoral Commission of Jamaica, the result would make Prime Minister Andrew Holness one of the shortest-serving premiers in the island nation's history.