“I think (German doubts) are positive, because I've been against Nord Stream 2 from the start,” she said of the project, designed to bring Russian gas directly to Germany.
“I don't think we should make ourselves dependent on Russian gas, so I think it's good if there are new conversations about that,” she told Danish news agency Ritzau.
Environmental challenges and American sanctions have already hindered Nord Stream 2, which is led by state-owned Russian gas giant Gazprom.
Germany had long defended the Baltic Sea pipeline — set to complement the existing Nord Stream 1 link opened in 2012 — against opposition by fellow EU countries Poland and the Baltic states as well as Ukraine, a major gas transit country.
But Chancellor Angela Merkel this week said she would not rule out possible consequences for the pipeline if Moscow's response to the Navalny poisoning fails to satisfy Berlin.
Almost all of the 1,230-kilometre (760 miles) length of Nord Stream 2 has already been built, but construction has been on hold for months as the US threatened sanctions against participating companies.
Denmark last year was the final country to give its green light for the pipeline to pass through its waters — months before Frederiksen came to power.
Copenhagen has denied any pressure from abroad on its decision, but has long had a delicate balancing act to strike between its two major allies Germany and the US.
When Secretary of State Mike Pompeo visited in July, he publicly hailed Danish energy policy.