Updated

Germany's most populous state holds an election Sunday, with polls showing good chances of victory for a center-left regional government that Chancellor Angela Merkel has sought to label as irresponsibly spendthrift.

About 13.2 million people are eligible to vote for the state legislature in North Rhine-Westphalia in western Germany, which includes Cologne, Duesseldorf and the industrial Ruhr region.

Sunday's election is the third state-level vote this year. It comes a week after a regional coalition of Merkel's conservative Christian Democrats and the pro-market Free Democrats — the parties that make up the national government — lost power in the northern state of Schleswig-Holstein.

It also follows setbacks for Merkel's austerity-led response to the eurozone debt crisis in French and Greek elections last weekend.

North Rhine-Westphalia, a traditional center-left stronghold, is voting three years ahead of schedule after its current minority government, made up of Germany's main national opposition parties, narrowly failed to get a budget passed in March.

Opposition leaders declared that the vote would send an important signal ahead of national elections due in late 2013. Merkel said it offered an opportunity for the region to elect a government that wouldn't take on "ever more debt."

While national polls show Germans backing Merkel's pro-austerity line in Europe, surveys suggest that the regional government of Social Democrats and Greens led by popular governor Hannelore Kraft has a good chance of emerging strengthened, with a majority in the state legislature.

Conservative challenger Norbert Roettgen, Merkel's federal environment minister, has had a lackluster and sometimes gaffe-prone campaign. He faced criticism for not committing himself to stay in state-level politics and for saying on a television show, in an apparent attempt at irony which backfired, that "regrettably" voters rather than his party would decide whether he became governor.

Roettgen irritated his party by declaring that Sunday's election would decide "whether Angela Merkel's course in Europe is strengthened or whether it is weakened by the re-election of a pro-debt government in Germany." Merkel said it was an important state election, "no more and no less."

The struggling Free Democrats' main aim is to win the 5 percent of votes needed to retain their parliamentary seats, building on a surprisingly strong performance last weekend in Schleswig-Holstein.

The upstart Pirate Party, which has surged in recent months with a platform of near-total transparency and Internet freedom but lacks policies on many issues — including the debt crisis — hopes to enter its fourth state legislature. That could complicate the center-left's chances of winning a majority.

While Germany's opposition will claim tail wind for next year's national vote from a victory, Sunday's election — unlike North Rhine-Westphalia's last vote in 2010 — won't change the national balance of power.

Two years ago, Merkel's coalition lost the state after five years in power there. That erased the national government's majority in the upper house of Parliament, which represents Germany's 16 states, and its position there has since weakened further.

Current national polls consistently show Merkel's conservatives as the biggest party. However, they forecast a parliamentary majority neither for her center-right coalition — which has become notorious for infighting on a wide range of policy issues — nor for the Social Democrats and Greens, who ran Germany from 1998 to 2005.

When the national election comes, Merkel's chances of holding on to power still look decent, though perhaps with a new coalition partner.