Berlin: Chancellor Angela Merkel is likely to win a fourth term as Germany goes to federal election on Sunday, according to various pre-poll surveys.

Merkel, already Chancellor for 12 years, had run a low-key campaign emphasising the country's falling unemployment, strong economic growth, balanced budget and overall stability in a volatile world.

Pre-election surveys have put Merkel's Christian Democrats (CDU/CSU) well ahead of centre-left Social Democrats (SPD) led by her challenger Martin Schulz, the Daily Express reported.

The CDU was in a comfortable lead with 37 per cent of the vote while the SPD was right behind with 20 per cent, suggesting the two parties will form a Grand Coalition in the Bundestag after the election day, according to surveys.

The populist, eurosceptic and anti-immigration party -- Alternative fuer Deutschland (AfD) -- was at 12 per cent, and will likely form the next government's main opposition.

The party is likely to enter the Bundestag after four years of its foundation and become the first far-right party in Bundestag after 1945. The party was almost elected into Bundestag in the last federal election with 4.7 per cent of votes, the report said.

In the run up to the election, Merkel made it clear that she would not cooperate with the AfD.

Merkel has pledged to get Germany's current 5.7 per cent unemployment rate, down from 11 per cent when she took office in 2005, to "full employment" by 2025. She has also vowed limited tax cuts and to keep Germany's borrowing at zero.

And she offers a steady hand internationally, with long experience of European Union negotiating marathons, tough talks with Russian President Vladimir Putin, and now of engaging cautiously with US President Donald Trump.

Polls suggest that Merkel's CDU and its Bavaria-only allies, CSU, will come in a few points short of the 41.5 per cent support they had in 2013 - Merkel's best result yet.

They put Schulz's SPD around or below the 23 per cent they won in their worst showing yet in post-Second World War Germany, which was recorded in 2009, the report said.