BERLIN - German Chancellor Angela Merkel faces off her Opposition challenger Peer Steinbrueck on Sunday night in their only TV debate before the September 22 general election as polls have been suggesting Merkel will win a third term.

The 90-minute TV debate in Berlin was aired live on mainstream German channels as a panel of four interviewers set the agenda and questions that covered issues including taxes, wages, Germany's policy in the eurozone debt crisis, as well as the Syria crisis. An estimated audience of 15-20 million tuned in to the debate.

People watch a TV duel of German Chancellor Angela Merkel of the Christian Democratic Union (CDU) with her challenger, the top candidate of the Social Democratic Party (SPD) in the upcoming German general elections Peer Steinbrueck, in a culture centre in Berlin, September 1, 2013, during an event organised by the SPD. German voters will take to the polls in a general election on September 22.[Photo/Agencies]

Both Merkel's conservative Christian Democratic Union (CDU) and Steinbrueck's centre-left Social Democrats (SPD) have campaigned mainly on domestic issues that dominated the debate.

Polls suggested that half of German voters watched the TV debate, while one in three said the debate could influence their choice. It is widely seen as Steinbrueck's last-ditch effort to win more hesitating voters as the elections will be held in just three weeks.

During the debate, Merkel took pride in Germany's low unemployment that is near the lowest levels since reunification in 1990,saying that Germany is the "motor of growth" and "anchor of stability" in Europe and she would like to continue the course.    

Steinbrueck, for his part, stressed greater social justice and reiterated his plan to introduce a national minimum wage of 8.50 euros ($11.35 dollars) per hour, pointing to the fact that 7 million people earned less than the proposed minimum wage. He also wanted to raise taxes on incomes above 100,000 euros to 49 percent from 42 percent.

However, Merkel said such tax hike plans would risk spoiling the good situation in the country. German economy expanded by 0.7 percent in the second quarter of 2013 compared with the previous quarter, the strongest quarter-on-quarter growth since the first three months of 2012. Strong economy in Germany boosted confidence that the eurozone would be brought out of the on-going recession soon.

The CDU party rules out tax increases and supports minimum wage deals struck by employers and trade unions in different industry sectors and regions.

On the eurozone debt crisis, Steinbrueck called for more solidarity measures for indebted eurozone members including Greece. In response, Merkel insisted on structural reforms and spending cuts by indebted countries and said it is her responsibility as chancellor to keep the reform pressure on Greece.

"If we do not follow this through we will see that these countries don't regain more jobs," she said, pointing to efforts that have been made to encourage growth.

Sharp-tongued Steinbrueck has criticized the Merkel government for misleading voters on the costs from another Greek bailout. He also urged her to be honest on how long Germany would have to save the debt-ridden country.

On the Syrian crisis, both candidates ruled out German participation in a military strike against Syria, as a recent poll showed that more than half of German people oppose military action by the western countries in Syria.

Merkel stressed the need to work toward finding a joint response from the United Nations to the alleged chemical weapons attack in Syria, while Steinbrueck said he would "greatly regret it" if the United States strikes without an international mandate.

The opinion poll by market research company Forsa showed last week that support for the CDU and its Bavarian CSU sister party stood unchanged at 41 percent, while the SPD party held at 22 percent.

However, it remains unclear whether Merkel's ruling coalition will survive the election even though her CDU and its Bavarian CSU sister party maintain a double-digit advantage over Steinbrueck's SPD in opinion polls.

The wild card is Merkel's junior ruling partner the Free Democrats (FDP), who stands at the threshold of 5-percent minimum support for entering into the lower house of parliament. Should the FDP fails to garner 5 percent of votes in the election, Merkel may be forced to form a coalition with the SPD.

When it comes to personal popularity, the gap is wider for the two candidates, with an earlier poll for state broadcaster ARD suggesting that Merkel claims a 68-percent approval rating among voters, maintaining her position as the most popular politician in Germany.

Another opinion poll issued this week for public TV station ZDF showed that 60 percent of respondents preferred Merkel as their chancellor, while only 31 would choose Steinbrueck for the job.    

Fifty-nine-year-old Merkel's domestic popularity owes much to sticking to principles in dealing with the eurozone debt crisis, including pressing indebted eurozone members to carry out austerity measures and reforms. Gravity-defying German economic performance during the crisis also helped to boost support for the Merkel administration.

Merkel joined the CDU and won her first parliamentary seat in 1990, and rose to the head of the CDU in 2000.She beat SPD chancellor Gerhard Schroeder in 2005 and became Germany's first female chancellor, chairing a grand coalition with the center-left SPD.

After her second victory in 2009, she was able to form a coalition government with the pro-business Free Democrats. She is considered as the most influential leader in Europe and one of the most powerful leaders in the world.

Steinbrueck, 66, served as finance minister during Merkel's first term as chancellor. He was nominated last year by SPD party leaders as their candidate in German federal elections in September. He was seen as the center left party's best hope to win back the chancellorship, which was held by SPD under Gerhard Schroeder from 1998 to 2005.

Steinbrueck's election campaign got off on the wrong foot as his profitable speaking engagements caused bad publicity. He earned 1.25 million euros ($1.61 million dollars) for speeches at private functions.

He also made gaffes in the early stage of the campaign including saying that he found the chancellor's salary too low and labelling Italian politicians as "clowns".

The leaders of smaller parties that will take part in the elections will have another election debate on Monday.