Armin Laschet, the election candidate for the Christian Democratic Union of outgoing Chancellor Angela Merkel, told a televised debate that talks must not take long.
"The new government must take charge very soon. I want us to get it done by Christmas at the latest," he told the Elefantenrunde show on ARD and ZDF.
Olaf Scholz, the vice chancellor, echoed his main rival in that he wanted the negotiations on forming a new government to be speedy.
"My wish is to get over it quicker. It would be absurd to name a date. But it would be good if it were over by Christmas," he said.
The remarks from the pair come on the heels of exit polls indicating that the left-leaning Social Democratic Party is maintaining a narrow lead ahead of the Merkel's CDU party.