Whitelock becomes a Highlander
Squire has played for the Chiefs over the last two seasons, although his appearances were limited this season due to injury. He has played a significant role in the success of the Tasman team over the last few National Provivial Championship seasons as a strong ball carrier who can breach defences.
Whitelock, an All Black in 2013, has played 50 Super Rugby games and will help to add further depth to the Highlanders loose forward stocks after the departures of Nasi Manu and John Hardie.
Highlanders head coach Jamie Joseph added: "We are delighted to have secured Liam's and Luke's services. We were looking for a strong ball carrying No.8 who would suit our style of play and we believe Liam fits that description.
"Luke's Super Rugby experience and versatility will be a real asset to our group and we're looking forward to having him join the Highlanders."
Whitelock said: "[I am] looking forward to coming down to Dunedin and being with the Highlanders next year. I have heard a lot of great things about the culture that has been developed down there."
Squire also commented that he was "looking forward to getting down there, getting to know everyone and seeing what Dunedin is all about".