The 2009 world champion, who joined the Woking based team last year as the reigning title winner, said earlier this year he might stay "for three years, five years … I don't know".
Team boss Martin Whitmarsh added: "If Jenson says he is totally committed and wants to do 'x' more years, then I suspect that we could quickly come to an agreement."
But after Red Bull's Sebastian Vettel and Ferrari's Fernando Alonso recently signed new long-term contracts, Button on Wednesday denied he is poised to do the same.
"For me it makes no sense to sign a long-term contract," he told the Swiss newspaper Blick. "I don't know how I'm going to feel in a few years.
"I can't imagine racing at 40," said the 31-year-old. "I just want to race for as long as I can win," added the Montreal winner.
"McLaren has an option on me for next year, that's all I know. Many of my colleagues don't hesitate to secure for the long term, but I like it when my future is open," Button insisted.
He denied he has had any talks with McLaren about his future yet.
Button said he is still hungry for more titles but will be eternally satisfied with his 2009 triumph.
"It still feels like yesterday and it will even when I'm old and grey. If I didn't win any more championships I definitely wouldn't leave formula one thinking that I've missed something," said the Briton.
"But the hunger for victory doesn't disappear so easily. I will stop when I'm bored to keep going around in circles, or if I'm not fast enough," he added.