Merkel told a closed session of the German parliament's foreign affairs committee on Wednesday that she would need to coordinate with other EU leaders after British legislators rejected the withdrawal agreement the evening before.
"For me it is clear that there cannot be any renegotiations," Merkel told the meeting, two participants said.
British Prime Minister Theresa May will try to forge a consensus in parliament on a Brexit divorce agreement after the crushing defeat of her own deal left Britain's exit from the EU in disarray 10 weeks before it is due to leave.
Merkel said the idea of pushing back Brexit beyond the scheduled date of March 29 was a "fictional question", the participants said.
Merkel said she was open to making further clarifications to a declaration on Britain's future relations with Brussels, but it was up to London to say what it wanted after the parliamentary vote, the participants said.
Before entering the meeting, Merkel told reporters it was necessary to keep trying to secure an orderly Brexit but stressed that Germany was prepared if Britain did end up exiting the EU in a disorderly fashion.
She said she regretted that the British parliament had rejected the deal negotiated with the EU and May needed to say how Britain would proceed.
"We think now it is up to the British side," Merkel said. "We want to keep damage to a minimum, and there will be damage with the departure of Britain."
"We will of course try to find an orderly solution but we are also prepared for the scenario that there may not be an orderly solution," Merkel added.
In the meeting of the foreign affairs committee, Merkel said the British parliament's decision was "pretty extreme", the participants said. (Reporting by Andreas Rinke, writing by Thomas Escritt and Michelle Martin; Editing by Alison Williams)