The signings of props Chris King and Bronson Murray and hooker Jason Rutledge shore up the front row while outside backs Kade Poki and Siale Piutau have also signed new deals with the franchise.
King and Poki have signed contracts for two years while the other three players have signed for one year.
It is a big move for Poki, who appeared to be on the outer six months ago after missing out on any Super 15 contract with a New Zealand franchise, and was looking for a move overseas.
But good form with the Highlanders, despite having a to carry a nagging knee injury, has led to his staying in the south with the Highlanders for the next two years.
Highlanders general manager Roger Clark said it was pretty pleasing to get players tied down for next season.
"It's nice that these guys have all committed to next season and it gives us confidence that we have retained a good core for next season," Clark said.
The aim of the coaching staff was to retain a good bulk of the players for the 2012 season and showed the attraction of playing for coach Jamie Joseph.
Captain and prop Jamie Mackintosh had yet to sign a deal to stay at the franchise next season but Clark was not overly concerned, saying Mackintosh wanted to concentrate on playing at this stage of the season.
Centre Kendrick Lynn was the other player the franchise wanted to sign again for next season and negotiations were continuing.
The Highlanders wanted to sign 24 players and then have eight spots open in the squad for next year.
Those spots would come from players who performed well in the ITM Cup and players from other franchises who were coming off contract.
The Highlanders have been linked with other New Zealand players such as Hurricanes backs Ma'a Nonu and Hosea Gear, and All Black hooker Andrew Hore, also from the Hurricanes.
Clark would not comment on the likelihood of players coming from other franchises to the Highlanders.
But with new Chiefs coach Dave Rennie appearing to have a clean-out and Mark Hammett clearing the decks at the Hurricanes, players will be become available.
Hore looks unlikely, because of his age and the fact the Highlanders already have an experienced hooker in Rutledge.
Wellington hooker Dane Coles could be in the Highlanders' sights but the Hurricanes appear keen to hang on to him, especially with Hore departing.
Clark said there was also the chance of getting an overseas player under rules introduced last year by the national union.
The Highlanders could not compete for an overseas player on money, Clark said, but there were always players looking for a challenge.
