In a new interview, the music mogul says he is hopeful of another album or tour for the lads.
He told The Sun newspaper: “You know, it’s fun being out there on your own but what I hope is going to happen is that they remember now how much fun it was being in a group.
“I always believe that you don’t make rules, you break the rules. So there’s nothing to stop them, if they want to, getting together for a tour, for an album.
“I made it absolutely clear, obviously, ‘We’re in’.”
And Simon confessed that there was a potential for the original five strong group turned four piece to even reunite as a trio but admitted “it wouldn’t be the same”.
It was previously reported that Simon was "determined" for the group to get back together.
The insider added to The Sun newspaper: “Simon has always regarded the band as being on a break, rather than over, and although there are no confirmed plans at the moment for them to get together again, it is absolutely his ambition and belief that the guys will be reunited.”
Speaking to the tabloid, Louis Tomlinson said he found the group's decision to go on a break "difficult" at first.
But he reflected: “If you asked me now if I think it’s the wrong decision, I don’t think it was.
“I think the market and the fans and everyone had had so much of One Direction that regardless of any individual ventures, the market could do with a two-, three- or however long break away from us.”