Halfpenny, whose tally of 801 points in 101 Tests put him third in Wales’ all-time points chart behind Neil Jenkins and Stephen Jones, joined Cardiff as a player-coach last summer.
The former British and Irish Lions full-back made his final professional outing in May when he came on for the closing stages of the Blue and Blacks’ win against Stormers at the Arms Park that sealed a place in the United Rugby Championship (URC) play-offs.
Halfpenny bolsters Tandy’s growing management team after he initially worked with just two permanent assistants – Matt Sherratt and Danny Wilson – following his appointment as head coach last summer.
This summer he has brought in defence coach Peter Murchie, contact area specialist Dan Lydiate and scrum coach Paul James.
Tandy is pleased to add Halfpenny as interim kicking coach to work closely with Sherratt.
“His playing record speaks for itself and it’s great to get him on board with us as he continues to develop his coaching career,” said the head coach.
“Our young backs will benefit a huge amount from the knowledge and experience that Leigh has to share.”
Wales open the Nations Championship against Fiji at Cardiff City Stadium on Saturday (14:10 BST) before trips to Argentina and South Africa.
