Expanding the staff would allow the coaches to have more specific roles, making it easier to focus on what needed to be done to make the team successful.
Otago coach Tony Brown was added to the Highlanders' coaching team this week, meaning the squad for next season will have four full-time coaches.
Joseph will work on the set piece and some of the attack, Scott McLeod will be the defence coach, Jon Preston will be working on players' individual skills, and Brown will be the attack coach.
Joseph said the other Super 15 teams around the country had four coaches, so the Highlanders were simply catching up.
''You see with the Blues, the Chiefs and the Crusaders, they all have up to four coaches. The Blues have got two All Black coaches in there. The Chiefs have Wayne Smith and three other guys,'' he said.
''The Crusaders made a change when Daryl Gibson left and now have four coaches.''
The Blues have Sir John Kirwan as head coach and he is assisted by former All Black coach Sir Graham Henry, All Black skills coach Mick Byrne and Grant Doorey.
The Chiefs have Dave Rennie as their head coach and he is assisted by Smith, Andrew Strawbridge and Tom Coventry.
Todd Blackadder at the Crusaders is assisted by Aaron Mauger, Dave Hewett and Tabai Matson.
Joseph said last year, from a coaching point of view, had been a bit messy and he said these new roles made it easier for the coaches to understand where they needed to focus their energies.
The Highlanders are without a scrum coach after Kees Meeuws left to pursue other opportunities.
Joseph said he was looking at something but it was not a major issue. The position was not full-time and Joseph said he was happy with the performance of the scrum last year. The Highlanders had the most successful scrum completion of any team in the competition, and experienced tight forwards Chris King and Brad Thorn could pass on their knowledge at the scrum.
The coaches have spent the past week going over the forthcoming season and talking about the game plan.
The Highlanders' 37-player squad will be named on Wednesday. The team will start training late next month.