Friedrich Merz, one of the front-runnners to succeed Angela Merkel as head of her conservative party, says he's ready to take on the anti-immigrant Alternative for Germany (AfD) party and snatch away half of their voters.

The AfD is represented in all 16 state parliaments in Germany, as well as the European Parliament and Germany's lower house of parliament, the Bundestag. That means the right-wing party won't disappear overnight, Merz said Wednesday in an interview with German tabloid Bild.

"But it can be cut in half," Merz said. The Blackrock Germany board chairman said he wants to win back frustrated voters who left Germany's mainstream parties - Merkel's Christian Democrats (CDU) and the Social Democrats (SPD) - to vote for the AfD.

The AfD's policies and rhetoric are openly nationalist and in part anti-Semitic and therefore the party is incapable of being in a government coalition or engaging in dialogue, Merz said.

Since its founding as a eurosceptic party in 2013, the AfD has taken a hostile stance toward German immigration policy. The party has garnered 13 to 16 per cent in recent surveys and is the largest opposition party in the Bundestag.

Voters expect politicians to guarantee the security of the country, Merz told Bild. "A state under the rule of law only works if the monopoly on the legitimate use of force belongs to the state - and no one else," he said.

There needs to be "a clear priority of internal security," he added.

Merz, a trained lawyer, has worked in the Dusseldorf office of global law firm Mayer Brown since 2005, offering counsel to companies on mergers. His clients include numerous DAX companies and international corporations.

Since 2016, he has also served as the board chairman of the German subsidiary of US investment management firm Blackrock, the world's largest asset manager.

In his interview with Bild, Merz answered a question about owning assets of at least several million euros with: "Anyway I'm not below that level."

The CDU candidate had initially demurred when asked by the tabloid if he belonged to Germany's wealthy upper class. "Well, I would count myself among the upper middle class."

After months of infighting in her three-way coalition government and two disastrous state elections, Merkel announced on October 29 that she would resign as leader of the CDU and said that her current term as chancellor would be her last.

Merz is joined by CDU Secretary General Annegret Kramp-Karrenbauer and Health Minister Jens Spahn in vying to replace Merkel as party chair - a decision that will be made at a party congress in Hamburg on December 7.