STOCKHOLM (Reuters) - Sweden`s centre-right government was expected to win re-election on Sunday, but a strong showing by the far-right might leave the ruling Alliance short of a majority and could rewrite the political map.

Two opinion polls on the eve of the election showed the government may or may not secure a wafer-thin parliamentary majority. A third showed that although the four-party Alliance would win, the anti-immigrant Sweden Democrats would hold the balance of power.

"There is a lot to do and large numbers of people make their choice at the last minute," the Swedish news agency TT quoted Prime Minster Fredrik Reinfeldt saying.

Two of the three polls showed the Sweden Democrats getting seats in parliament for the first time ever. Reinfeldt has called on Swedes to vote tactically to keep out the far right.

Voters face a choice on Sunday between a centre-right offering a leaner welfare model and more cuts in income taxes and a centre-left that wants the rich to pay more to fund schools, hospitals and care for the elderly.

The Sweden Democrats` main policy platform is to drastically cut immigration.

UNCERTAINTY

Should either main bloc fail to get a majority, it is unclear who would form the next government, with analysts warning that political uncertainty would undermine the Swedish currency and push up bond yields.

Social Democrat leader Mona Sahlin, who would become Sweden`s first woman prime minister if the opposition wins, said it was not too late for voters to elect the centre-left.

"We can get a Red-Green government on Sunday," she told a rally in central Stockholm.

"Every second, every minute hour that is left, up to 8 o`clock tomorrow...vote, and vote Red-Green."

The SVD/Sifo poll gave the Moderates, Liberal, Centre and Christian Democrats 49.9 percent of the vote against 45.3 for the opposition coalition. In that poll the Sweden Democrats were just short of the 4 percent needed to get into parliament.

The DN/Synovate survey gave the government parties 49.2 percent and the opposition of the Social Democrats, Greens and Left party 42.8 percent. DN/Synovate put support for the anti-immigrant Sweden Democrats at 5.9 percent.

That would give the Sweden Democrats 21 seats in the country`s 349-seat assembly.

A third poll, by United Minds, put the Alliance at 46.9 percent, the opposition at 43.9 percent and the Sweden Democrats at 7.2 percent, leaving them holding the balance of power.

Both main blocs have ruled out cooperating with the Sweden Democrats.

BDST: 1048 HRS, September 19, 2010