Profile: Australia's conservative leader Tony Abbott

CANBERRA (Reuters) - Australia may be headed for a hung parliament with an election-eve opinion poll showing the ruling Labor party has lost its slim lead and is now level with the conservative opposition, a worst-case scenario for investors.

Three independents, if elected on Saturday, may decide whether Labor or the conservative opposition forms government.

Here are key facts about 52-year-old opposition Liberal party leader Tony Abbott.

-- A pugnacious and socially conservative Catholic, Abbott became leader of the Liberal-National coalition in 2009 by rallying opposition to a carbon trading scheme. He took over an opposition trailing in opinion polls but has reversed his party's fortunes and may return it to power after its 2007 defeat.

-- The London-born Abbott opposes a range of issues, including a push to make Australia a republic, embryonic stem cell research, same-sex marriages and carbon trading to combat climate change. His book on Australian conservative politics published in 2009 was titled "Battlelines."

-- Graduated from the University of Sydney with a law and economics degree. He was a Rhodes Scholar at Oxford University, majoring in politics and philosophy, and won two Blue awards in boxing.

-- Trained to be a priest at St Patrick's Seminary, Sydney, in the mid-1980s. Abbott was later given the nickname "The Mad Monk" by his political critics.

-- Journalist at Australia's now defunct "The Bulletin" monthly news magazine and The Australian newspaper.

-- Press secretary and political adviser to the Liberal party's opposition leader, John Hewson, 1990-93.

-- Executive Director of Australians for Constitutional Monarchy from 1993-94, opposing moves for Australia to become a republic and replace its constitutional monarch, Queen Elizabeth II, with an Australian president. He has written two books in defense of Australia's existing constitutional system, "The Minimal Monarchy" and "How to Win the Constitutional War." defense of Australia's existing constitutional system, "The -- Entered parliament 1994. Minister for Employment Services in 1988 and promoted to cabinet as Minister for Employment, Labor and Small Business in 2001. Minister for Health and Aging from 2003.

-- After the conservative government lost office in 2007, Abbott held a series of shadow ministerial roles ranging from housing to indigenous affairs.

-- In December 2009, became leader of the Liberal-National opposition coalition by rallying opposition to a carbon trading scheme to combat climate change.

-- Abbott is a leading conservative intellectual who has steered conservative parties toward the right. He has pledged to dump the previous Labor government's new 30 percent mining tax, not introduce a carbon price, and introduce tougher border security by reopening South Pacific detention camps for boatpeople.

(Reporting by Michael Perry; Editing by Balazs Koranyi)