Germany's chancellor-in-waiting Friedrich Merz has promised to "massively expand border controls" once the country's next coalition government is in place.

Merz's conservative Christian Democratic Union/Christian Social Union alliance, known as the CDU-CSU, emerged as the winner in February's parliamentary election, ahead of the far-right Alternative for Germany, or AfD, and the Social Democrats, or SPD.

The CDU-CSU has shunned the AfD and is in coalition talks with the SPD, which led the previous coalition government that collapsed toward the end of last year, bringing forward an election that had been scheduled to take place in the fall of 2025.

Merz represents the same party as Angela Merkel, the chancellor of Germany from 2005 to 2021, who famously encouraged immigration in a 2015 speech by saying "we can do this".

But Merz's stance is very different to Merkel's and in a speech during an election campaign dominated by the issue of immigration, he made a point of using the phrase "we can't do this", saying millions of asylum seekers could not be absorbed by Germany "no matter how hard we try … I promise you this, under my leadership, the numbers will drastically go down".

Immigration control, he said at the weekend, would be high on the agenda of his new government.

"In coordination with our European neighbors, we will reject people at our shared borders, including asylum seekers," he added. "We want to take all legal measures to reduce irregular migration overall. We will massively expand border controls from the first day of our joint government, and we will also significantly increase the number of rejections with these border controls."

Speaking in Berlin, Merz said preliminary agreement had been reached on a number of major policy issues and further coalition talks were likely to take place this week.

Merz has previously said he hopes to have a functioning government in place by Easter. Both sides, he added, shared "the conviction that we have a great task ahead of us, that we will soon need a new government in Germany with a parliamentary majority".

But leaders of the AfD, which is excluded from sharing power with mainstream parties by their so-called firewall of non-cooperation, accused Merz of breaking campaign promises and giving in to what they called the SPD's "debt madness" before he had even assumed power.

In return for this, said AfD leaders Alice Weidel and Tino Chrupalla, Merz "has only received vague promises and formulaic compromises in migration policy, full of reservations and backdoors".