Even if the German defence minister's Brussels appointment is confirmed later Tuesday, she would not take office until November 1, after the Brexit cut-off, but her view may carry weight.
"I stand ready for further extension of the withdrawal date should more time be required for a good reason," von der Leyen told a European Parliament ahead of a vote on her candidacy.
Von der Leyen's remarks triggered howls of derision from pro-Brexit members of the European Parliament, as said sought to tackle key areas of uncertainty caused by Britain's shock June 2016 vote to leave the bloc.
She stressed, for example, the importance of preserving the rights of citizens on both sides of the divide and maintaining peace on the island of Ireland: "These two priorities are mine too."
Von der Leyen faced the European Parliament on Tuesday ahead of a knife-edge secret vote to confirm
her in Brussels' top job.
The 60-year-old conservative will replace Jean-Claude Juncker as president of the European Commission if she secures a majority in the Strasbourg assembly.
If she fails -- and the ballot could be close -- then Europe faces a summer of institutional infighting between parliament and the 28 EU leaders.
And if her victory is close or is secured only thanks to eurosceptic members, her position will be weakened even before she takes over as the commission's first female leader in November.
She has had barely two weeks to make her case since the leaders declared her the nominee after a tense three-day summit, casting aside candidates backed by parliament.
But von der Leyen has responded with a series of written promises to the main centre-right EPP, socialist S&D and liberal Renew Europe blocs that she hopes will get her the necessary 374 votes.
And on Tuesday, she was broadly well received by sceptical lawmakers when she tried to reassure them of her environmental credentials and that she would build an inclusive five-year programme.
"I will put forward a green deal for Europe in my first 100 days in office. I will put forward the first ever European climate law which will set the 2050 target in law," she said.