The former England captain had hoped to reach a century of caps in Fabio Capello's first game in charge against Switzerland next week.
Ex-Toon Boss Backs Beckham!
However, the 32-year-old midfielder was omitted from the Italian's first squad due to lack of match practice with MLS not in season.
Gullit: "If he wants to continue then I'll do everything I can to help. It's up to him - but why not?
"If David goes with the national team then I will have to rest him, otherwise he will not be able to play him at his best.
"To play for your country and get 100 caps is the best thing that can happen."
Gullit believes Beckham was one of England's best performers in their ill-fated Euro 2008 qualifier against Croatia and sees no reason why he should hang up his international boots just yet.
"I was not bitter that England didn't qualify for Euro 2008 because I get Beckham for an extra one-and-a-half months.
"That's the advantage of England not qualifying.
"What did everyone say after England played against Croatia? They said that Beckham was the best player on the pitch.
"I've seen him playing in our friendly games and he's been playing out of his skin. I think the period between 28 and 34 are the best years of your career."