BERLIN - A car radiator repair boss, a longtime soldier and an economics professor - they are unlikely bedfellows leading the charge of an anti-immigration party that has come from nowhere to disrupt the cosy, stable world of German coalition government.

Andre Poggenburg, Uwe Junge and Joerg Meuthen steered the Alternative for Germany (AfD) to big gains in three regional elections last weekend as voters disenchanted with Chancellor Angela Merkel's liberal migrant policy turned to them in droves.

It was partly a measure of success of the three-year-old party's strategy of offering up leaders from diverse walks of life to woo voters across the social spectrum. Poggenburg who campaigned in a poor eastern state saw himself as championing the "non-academic", for example, while Meuthen delighted in debating the finer points of the German constitution in the richer west.

About three-quarters of Germans now expect the right-wing party to win its first seats in the national parliament in a general election next year, a survey by YouGov showed on Friday.

The rise of the AfD followed gains by other European anti-immigrant parties including France's National Front, and has punctured the centrist consensus around which the mainstream parties have formed alliances in Germany. It added pressure on Merkel to find a solution to Europe's refugee crisis.

Yet immigration was not even on Poggenburg's mind when he joined the party in 2013. He says his main concern was that a distant elite in Berlin was deciding on bailouts for crisis-stricken euro zone states over ordinary Germans' heads.

Now the AfD leader in the eastern state of Saxony-Anhalt feels the same about the refugee crisis and is angry the government has let in so many migrants - over a million arrived last year - without consulting German citizens.

"The borders were flung open and now everyone is being forced to pay the price socially and financially while suffering from a loss of domestic security," said the 41-year-old, who grew up in the former Communist East Germany and runs a business repairing car radiators and heat exchangers.

"Everyone is now expected to stump up for a decision they didn't even make," he told Reuters.

Poggenburg secured a record 24.2 percent of the vote for the party in the eastern state of Saxony-Anhalt in last weekend's election, making it the second-biggest force there behind Merkel's Christian Democrats (CDU).

He plans later this month to close his company after around two decades and devote himself to politics full-time.

'TRAUMA OF DEATH'

Poggenburg said he could never have imagined working for a political party a few years back because there was not one where he felt at home. But in the run-up to the 2013 federal election, the AfD, which campaigned against the euro and bailouts, caught his eye.

Poggenburg, who joined the party in autumn 2013, has said he sees himself as representing its patriotic, non-academic and self-employed members.

The party's support was stronger in Saxony-Anhalt, where unemployment is running at 9.8 percent, than in the richer western states of Baden-Wuerttemberg and Rhineland-Palatinate.

"If someone says we've got high unemployment and we couldn't invest here or there ... and then all of a sudden there's enough money to finance a multi-cultural experiment, of course people will say 'we've had enough, it can't go on like this and we want a party that tackles this problem'," Poggenburg said.

His story is rather different to that of 58-year-old Junge, the AfD's frontman in the western state of Rhineland-Palatinate, where the party got 12.6 percent of votes.

A lieutenant colonel who served twice in Afghanistan, Junge was born in western Germany after, near the end of World War Two, his parents and grandparents fled their homes in an area that then belonged to Germany, but is now part of Poland, as Russian troops advanced.

His grandparents often told him stories of relatives being killed or injured and they never got over leaving their property behind so he says he grew up with their "trauma of death, wounds and the loss of home".

A CDU member for 34 years until 2009 who says his role model is former West German Social Democrat Chancellor Helmut Schmidt, Junge told Reuters he was concerned that migrants would push up German unemployment and weaken the health system.