Brad Thorn's remarkable rugby career will extend another year after committing to the Highlanders in 2014 embroidery logo.

The 38-year-old lock is one of three Highlanders to add a year to their contract while Crusaders flanker Shane Christie will shift south to play at least one season.

First five-eighth Hayden Parker and flanker TJ Ioane are the other two returning players, joining Thorn in a side who won just three of 16 games in 2013.

Coach Jamie Joseph said former All Black and Australian rugby league international Thorn will play an important role next year in seeking to rebound from a disappointing campaign.

"Brad brings a great deal of professionalism to any team he plays for.

"His work ethic, experience and leadership are invaluable for our team and he has been one of the most consistent players this season."

Thorn became Super Rugby's oldest player this year when he surpassed former All Blacks captain Tana Umaga and will be 39 when the competition kicks off next year philippines real estate.

The core of the Highlanders' 37-man squad has now been retained, including star fullback Ben Smith, who recently signed a four-year deal .

Joseph said Parker's retention, alongside the already-secured Lima Sopoaga, is important as first-choice first five-eighth Colin Slade is still considering a possible return to the Crusaders.

Ioane had stepped up and filled a void in his first season, covering for the season-ending injury suffered by Nasi Manu.

Joseph was familiar with Tasman flanker Christie, having coached him in the New Zealand Maori side.

The Highlanders confirmed they are seeking dispensation from the New Zealand Rugby Union to include Japan-bound midfield back Tamati Ellison on next year's roster as an overseas classified player.