Robertson, 43, lifted the Super Rugby title this summer in his first season as head ccoach of the Crusaders.
He joins Barbarians head coach Robbie Deans for the European leg of the tour which will see the BaaBaas take on New Zealand at Twickenham on November 4 before facing Tonga at Thomond Park in Limerick on November 10.
Robertson won 23 caps in the back row for New Zealand and coached Canterbury and the New Zealand Under 20 side before being appointed to his Crusaders role.
“I’ve got a great regard for the Barbarians,” said Robertson.
“I got invited to play but couldn’t get released at the time so it’s nice to be involved on the coaching side and the chance to work with Robbie’s a great opportunity."
Deans added: “You’ll certainly see Scott's passion for the game when he’s involved with us.
"He did a great job for the Crusaders in his first year and celebrated after the Super Rugby final with a break dance — so if he gets the chance to do that again, we’ll know we’ve done okay.”
The Barbarians are also in action next month in Australia, where former Wallabies coach Alan Jones takes charge of the team for matches against the Classic Wallabies (Lismore, October 24) and Australia (ANZ Stadium, Sydney, October 28).
Squads for both legs of the tour will be named in due course.