The singer and bass player appeared onstage with his old Guns N' Roses bandmate at London's The O2 venue for a few tracks last year, but while he has ruled out returning to the band, he enjoyed meeting with the singer again.
He said: "The cool thing about that was Axl and I got to reconnect. We're grown-ups, you know. There's been a lot silliness. Lawyers and bulls**t.
"You know, lawyers like to create a situation so that their jobs go on. And I know that. But it was just nice to reconnect. We had a nice dinner.
"That was much more important to me than actually getting up and playing. But it was fun playing with those guys. There are some really good players in that band."
Axl is now the only original member of Guns N' Roses after bitter splits with original guitarist Slash and Duff in the 90s, and while he continues with the band, the other two star together in Velvet Revolver, who are presently hunting for a new lead singer after Scott Weiland left in 2008.
Duff added to website Entertainment Weekly: "We had written a bunch of songs right around the era when Scott was on his way out, and right after that. So we've got stuff that we can give the singers to sing on. Like, 'Show us what you got. Write a lyric and a melody.' Because that's more than half the battle with singers."
One of the singers the group have had sessions with is Corey Taylor from Slipknot, although Slash has insisted they were only "trying him out," and he will not be join the group permanently.
Slash said: "We did work with Corey, but all we were doing was trying him out. But it didn't seem to fit to me. It didn't seem like the answer to the Velvet Revolver problem."
Duff also fronts the group Loaded, while Slash released his debut solo album last year.