MUNICH/POTSDAM, Germany (Reuters) - More than 8,000 people -- including hecklers blowing whistles -- showed up in Munich for one of German Chancellor Angela Merkel’s final speeches before Sunday’s national election that is expected to sweep her into a fourth term.

Merkel, whose conservatives have a solid double-digit lead over the Social Democrats, largely ignored jeers from hundreds of left- and right-wing demonstrators to deliver a stump speech focused on stability, security and a promise to avoid tax increases.

“Get lost,” “Merkel must go,” shouted some demonstrators as curious foreign tourists, in Munich for its famous Oktoberfest, snapped photographs of the German leader first elected in 2005.

Merkel, who has faced down similar heckling at many other rallies, especially in the former Communist east, admonished the peaceful but boisterous crowd: “Whistling and yelling certainly won’t ensure the future of our country.”

Merkel defended her 2015 decision to allow in about one million migrants as a humanitarian necessity but said she would prevent a repeat of the migrant crisis by doing more to fund programs in at-risk countries to keep people from fleeing.

“What happened in 2015 cannot and will not be repeated,” Merkel said, saying she would protect Europe’s borders.

At Berlin’s Gendarmenmarkt, Merkel’s main rival, SPD leader Martin Schulz urged supporters to make their voices heard, saying that high voter turnout could help offset growing support for the far-right Alternative for Germany (AfD).

Schulz, flanked by hundreds of red balloons, decried the AfD as “gravediggers of democracy,” and said his party, which also opposed the rise of Nazis in the 1930s, would do all it could to fight the anti-immigrant group.

“You are our enemies and we will defend democracy in Germany,” he said. “The more people vote, the smaller will be the share of the far-right.”

Schulz told Bild newspaper he had not given up hope of victory and 37 percent of voters were still undecided.

AFD POISED TO MOVE INTO PARLIAMENT

Support for the AfD, which was founded in 2013 during the euro zone crisis but has won support since 2015 with its anti-immigrant rhetoric, is running around 11 percent. That means it will become the first far-right party in more than half a century to clear the 5 percent hurdle and enter parliament.

The AfD, which has already won seats in 13 of 16 state legislatures, promised to reenergize debate there after four years of “grand coalition” rule by the two major parties.

Slideshow ( 10 images )

“It must get into the Bundestag lower house so that debates happen again,” the AfD’s top candidate Alexander Gauland told Reuters in Brandenburg’s regional parliament. “This parliament...has become totally boring.”

Gauland said the AfD would bring in “completely different political suggestions” after four years of agreement between the parties of Merkel and Schulz on issues ranging from sanctions against Russia, the NSA spying scandal or on the refugee issue.

Schulz described Gauland as “shameless”. Gauland provoked outrage by saying at a recent rally that Germans should no longer be reproached with the Nazi past and should take pride in their World War Two soldiers.

Slideshow ( 10 images )

“The language that he speaks is the language of the Harzburger Front,” Schulz said, referring to a radical right-wing alliance in Weimar Germany. “The gravediggers of the Weimar democracy, they spoke like Mr Gauland.”

The mainstream parties have ruled out working with the AfD, which may emerge as the third largest party; but Gauland said it would ultimately work toward being able to govern in the medium or long-term.

Electoral arithmetic might yet push Merkel into another grand coalition with the SPD, or she may enter a three-way alliance with the pro-business Free Democrats (FDP) and environmental Greens.

The Forsa poll showed support for Merkel’s conservatives holding steady on 36 percent, while the SPD ceded 1 percentage point to 22 percent.

An Emnid poll put Merkel’s CDU and its Bavarian sister party at 35 percent, while the SPD was at 22 percent.