Berlin: Voting began on Sunday for Germany's federal elections, with Chancellor Angela Merkel tipped to retain power even after 12 years in office, the media reported.

Merkel is seeking a fourth term in office and to keep her Christian Democrat Party's (CDU) status as the largest presence in the Bundestag or the German national parliament, reports the BBC.

The CDU's coalition partner, the Social Democrats (SPD) led by Martin Schulz, a former president of the European parliament, is its main opponent.

The right-wing nationalist, anti-Islam Alternative for Germany (AfD) party is likely to gain seats in parliament for the first time.

The party has so far held seats only in regional government, but has grown in popularity during a campaign focused on immigration issues.

Other significant contenders include Die Linke (the Left), the Greens, and the Free Democrats (FDP).

Polling stations opened at 8 a.m. and will close at 6 p.m., the BBC reported.

The first exit polls are expected shortly after the voting concludes.

Some 61.5 million people aged over 18 are eligible to vote in federal elections, which are held every four years.

There are two separate votes -- one for a candidate in their constituency and one for their preferred political party.

The election is seen as important because it may result in six parties in the Bundestag for the first time since the Second World War.

Such a result could mean a change in the makeup of the current governing coalition.