* Exit polls show centre-right parties significantly ahead
* Centre-right coalitions possible
(Writes through with exit polls, comments)
By Jana Mlcochova and Jason Hovet
PRAGUE, May 29 (Reuters) - Centre-right parties took a large lead in the Czech parliamentary election and could form a majority coalition government, an exit poll released by Czech Television showed on Saturday.
The poll, released immediately after polling stations closed, showed the right-wing Civic Democrats at 20 percent of the vote, and they could easily form a coalition with other centre-right parties, which fared better than expected.
"If the results are like this, it would be a shock to the political scene. It would be a big victory for the right and a defeat for the left, mainly the Social Democrats," political analyst Milan Znoj said.
The poll also gave 20 percent to the left-wing Social Democrats, possibly quashing the fears of many Czechs that they would form a government backed by the Communists, who have not had any share of power since their totalitarian rule ended in the 1989 Velvet Revolution.
Social Democrats said it was too early to call, as left-wing voters may have declined to disclose their choice to pollsters.
"If the numbers were valid than it is not particularly cheerful but at the moment we must wait for the real numbers," Vice-Chairman Bohuslav Sobotka said.
RESULTS
The actual results, which may swing the overall picture due to the margin of error in exit polls observed in past elections, were expected to come in over the course of Saturday afternoon.
Czech voters have been split between leftist promises to ward off economic crisis and right-wing warnings that such policies would lead to bankruptcy. Analysts feared a close or inconclusive result could lead to months of negotiations and the formation of a weak cabinet unable to launch reforms.
Social Democrats have been backed by mostly older and less well off voters among the 10.5 million Czechs, while right-wing parties promising budget cuts and pension reform have a power base among younger and wealthier voters.
Drawn-out coalition talks could rattle investors who want a decisive government to shepherd a nascent recovery in the NATO member state after its economy fell 4.1 percent last year.
A main concern is whether officials can rein in a budget deficit that hit 5.9 percent of annual output last year and enact changes to pension, healthcare and welfare systems that have changed little in the 21 years since the fall of Communism.
The exit poll showed potential Civic Democrat allies, the conservative TOP09 winning 17 percent, the centrist Public Affairs with 11 percent and the centrist Christian Democrats at 5 percent, right on the threshold for winning seats.
"It is good the right wing scored well, we did not expect that due to all of the screw ups they have made," said Jiri Rotrekl, a 50-year-old agriculture engineer who voted for the Civic Democrats.
Analysts say right-wing warnings of bankruptcy may be overblown because public debt of 35 percent of gross domestic product is half the EU average.
But they say an ageing population -- retirees are expected to outnumber workers by 2050 -- will create large deficits in the pay-as-you-go pension system.
The Civic Democrats have proposed private pension accounts, while the Social Democrats say no change is needed for now.
Interim Prime Minister Jan Fischer, who took power after a Civic Democrat government collapsed a year ago, has promised to hand over budget options to whichever government emerges from the election and subsequent talks.
It would ensure either side can cut the deficit to the EU-prescribed level of 3 percent of GDP by the Civic Democrats target of 2012 or a year later for the Social Democrats, with market watchers preferring the rightist party's scenario.