* PM Fico leads polls but opponent catches up
* Voters anxious about giving ruling party too much control
* Challenger is political novice with business background
By Jan Lopatka
SKALICA, Slovakia, March 13 (Reuters) - Slovak Prime Minister Robert Fico, long the odds-on favourite to be elected president on Saturday, now faces a tight race after voters wary of giving him too much power started backing a rival.
Fear of a overly dominant Fico has boosted support for Andrej Kiska, a political novice who made millions of dollars in consumer lending before becoming a philanthropist in 2006 to run a charity network for families with ill children.
Polls show Kiska, 50, trailing by around 9-15 percentage points but the gap is narrowing fast and some pollsters give him a chance of beating Fico in the run-off round on March 29. The first round will take place on March 15.
"The president must be non-partisan, independent, so the government has a healthy counterbalance," Kiska told Reuters.
The prime minister has most of the power in Slovakia's parliamentary system, but the president - despite his limited responsibilities - is directly elected.
If Fico, an energetic 49-year-old lawyer, wins the election, he could install a party ally as prime minister. Critics say he could then hardly resist the temptation to boost the president's limited powers through constitutional changes.
That would give his centre-left Smer party a stranglehold on the executive branch in Slovakia, a country of 5.5 million people that emerged in 1993 from the breakup of Czechoslovakia.
"He is an ambitious young politician who would want to design a semi-presidential system, if not a presidential one," said political scientist Samuel Abraham, head of the BISLA liberal arts school in Bratislava.
"Smer has the majority of seats and it can't be that they have the president as well," said truck driver Miroslav Rehak. "I'm not saying having Kiska is like winning the lottery, but it will certainly be a change and something new."
SUPPORT FOR UNDERDOGS
Slovakia is host to scores of foreign investors such as Volkswagen or U.S. Steel. Fico's opponents say a concentration of power could worsen the business environment by limiting the checks and balances in the justice system.
Central Europe has no lack of domineering politicians. Prime Minister Viktor Orban is in full control in Hungary and Czech President Milos Zeman has engaged in a string of clashes with political parties over his authority.
Slovak voters have shown they can unite behind an underdog. Outgoing president Ivan Gasparovic was elected for the first of his two five-year terms in 2004 because voters united against former authoritarian prime minister Vladimir Meciar.
Kiska is riding a wave of popular anger at sleaze and distrust in established parties, much like another newcomer Andrej Babis whose movement finished a close second in the Czech parliamentary election last year.
Slovakia's economic reforms, growth and euro adoption in 2009 put it among the most successful post-communist countries, but most past governments been blamed for privatisation scandals and other forms of graft.
"Corruption is growing through the society and the fish smells from the head," Kiska said.
The president's powers to fill some top judicial posts should not fall into the hands of the ruling party, he said, because the judiciary needed more diverse control to secure the rule of law - a key factor for investors.
Political analysts said Kiska lacks any clear political vision. The soft-spoken father of four refuses to be labelled as right or left-wing but declares support for the euro, economic openness, foreign investment and small businesses.
FICO BETS ON COMPETENCE
Fico has denied he would seek more powers and campaigns on the need to have a president with deep experience like his six years as prime minister.
"It will be very, very important that people with experience from standard politics can influence developments in our country and the European Union," he said last week.
Fico set up Smer in 1999 and retains a dominant position in the party. A loyal follower, Robert Kalinak, is a leading candidate to replace him as prime minister.
While lashing out against big companies and slapping extra taxes on banks and utilities, he has welcome foreign investors and kept social peace despite unemployment of 13.6 percent.
Fico relishes in his alpha male image. Last year he beat an elite army unit by doing 1,001 push-ups in half an hour, an athletic display reminiscent of Russia's Vladimir Putin.
Last week, limping with an Achilles heel injury from playing soccer, he toured Slovakia to tell jokes to packed town halls, at Smer party gatherings celebrating International Women's Day. (Editing by Tom Heneghan)