The Brumbies are mentoring three coaches this week - including former NSW Waratahs point-scoring ace Peter Hewat - from the Suntory Sungoliaths, the club that has loaned Smith to the Brumbies until the end of next month.

While the Brumbies are yet to formally request an extension for Smith's loan, the coaching co-operation is a promising sign the relationship between the two clubs is blossoming.

Brumbies coach Jake White has indicated he would approach Suntory to seek a contract extension for Smith only if the Brumbies were tracking for a finals finish.

But White said the Brumbies must remain respectful of Suntory's contract.

Smith has become a vital cog for the Brumbies, especially since a season-ending injury to David Pocock, starring in his four Super Rugby games so far this season.

Hewat and two Suntory assistants are in the capital this week to learn from the Brumbies coaches before the clash with the Southern Kings on Friday night.

Hewat played with Smith for two seasons in Japan and is not surprised the 32-year-old flanker can still dominate in Super Rugby.

''He's been the best player in Japan the last couple of years and I think he's grown as a player,'' Hewat said of Smith.

''Being over in Japan, he's been to France and he's experienced different styles.

''He's matured as a player and is probably in the best shape of his career so it didn't surprise me at all with the way he didn't miss a beat coming back to Super Rugby. He's just a freaky player.''

Suntory's coaching visit to the Brumbies came at the request of the former coach of both teams, Eddie Jones. New backs coach Hewat, a forwards coach and strength and conditioning coach have joined the Brumbies this week as part of the growing bond with Suntory.

Jones has been a key figure in forging a strong partnership between the Brumbies and Suntory in the past two seasons.

He helped recruit Smith last month for an Australian rugby comeback at the end of Suntory's triumphant Japanese campaign.

Jones has also been working with White as a consultant.

For Hewat, it's the second time in less than 12 months he's made a surprise appearance at the Brumbies.

Suntory loaned the star back to the Brumbies last year when they were hit by a playmaker injury crisis following season-ending injuries to Christian Lealiifano and Matt Toomua. He added experience to the Brumbies' roster on a short-term deal, but in the end he wasn't needed on the field with Zack Holmes capably stepping up in the No.10 jersey.

In his Super Rugby career Hewat scored 365 points for the Waratahs and, despite playing just three seasons, he's the second highest point scorer in the club's history.

Now retired, Hewat is preparing for his first season of coaching.

''I always wanted to get into coaching and that's one of the reasons I went to Suntory,'' Hewat said.

''Any aspiring coach wants to coach at the highest level they can … if things go well in Suntory then I'd like to coach the best level I can and if that's Super Rugby then I'd love it.''