A car used by German far right leader Frauke Petry has been set alight on the eve of an election that is expected to see her party make significant gains.

Ms Petry, leader of the anti-immigrant Alternative for Germany (AfD) party, posted a photo of the burned-out vehicle on Twitter with the caption: 'An arson attack was committed on my car yesterday. Is this what we have come to.'

Elections on Sunday could see Angela Merkel's Christian Democratic Union (CDU) ejected from Berlin's state government, as voters warm to the AfD's populist message.

Frauke Petry, leader of Alternative for Germany (AfD), posted this photo on Twitter with the caption: 'An arson attack was committed on my car yesterday. Is this what we have come to'

Elections on Sunday could see Chancellor Angela Merkel's Christian Democratic Union (CDU) ejected from Berlin's state government, as voters warm to the AfD's anti-immigrant message

Tomorrow's vote comes two weeks after the CDU was beaten into third place by the AfD in Chancellor Merkel's home state of Mecklenburg-Western Pomerania.

The CDU has long been weak in Berlin but another feeble result, though not immediately dangerous to Mrs Merkel, would keep up political pressure on her.

The Chancellor's opening of Germany's borders to migrants last year featured prominently in Mecklenburg, although the influx has diminished drastically.

Ms Petry's car caught alight in the eastern city of Leipzig on Friday night, in what police are treating as an arson attack.

Last year unknown attackers set fire to the car of AfD deputy leader Beatrix von Storch in Berlin.

Mrs Merkel has defended her immigration policy against her critics, including the AfD.

She said at a rally on Wednesday: 'It is not enough ... to know who is to blame, it is not enough just to know what you're against.

'We need good solutions that hold our society together.'

Local issues are more prominent in Berlin, a city of 3.5 million.

Protesters wore masks of Ms Petry and Donald Trump at a protest against the Transatlantic Trade and Investment Partnership in Berlin today

Disillusionment with the governing parties is high over the capital's notoriously inefficient bureaucracy and issues such as years of delays in opening its new airport.

Mayor Michael Mueller's centre-left Social Democrats lead the local government, with the CDU as junior partner in a bad-tempered alliance.

In Berlin, Mrs Merkel's conservatives have stressed law-and-order issues, with the current state interior minister leading calls for a ban on face-covering veils.

Polls suggest support for the Social Democrats will sink to at most 24 percent, while the CDU should poll around 19 percent.

The three-year-old AfD is confident, plastering Berlin with posters proclaiming 'First Schwerin, now Berlin!' Schwerin is Mecklenburg's state capital.

This banner contains the word 'Volkisch', a term that roughly means 'nationalist', and is associated with the Nazi party. Ms Petry recently called for the term to be 'revalued'

Still, Ms Petry cautions that Berlin 'is a significantly more difficult environment to campaign in.'

Polls show its support at up to 15 percent in Berlin. The capital is somewhat less promising territory than rural Mecklenburg, where it won 20.8 percent to finish second.

Polls show nationwide support for AfD of between 11 and 14 percent.