Mr McLachlan said the ambush of the meeting was very disappointing and the Friends would try and find another way to move forward.
He estimated up to 70 people were at the meeting.
But board chairwoman Kristy McDonald saw the meeting in a different light.
She said it was heartening to see a good turnout of Friends who clearly supported the Aratoi board.
Ms McDonald said Owen Prior put a motion forward for the removal of Allen Hair from the Friends committee but that was refused by Mr McLachlan.
Anne Atkinson presented a letter signed by 30 members of the Friends calling for a special meeting to elect a new committee which would have to be held within three weeks according to the Friends constitution.
Ms McDonald rejected any suggestion that Saturday's meeting had been hijacked.
She said many were angry the meeting invitation had not been sent to all Friends, as members of the board has been excluded.
She said the anger and frustration expressed at the meeting by Friends against their own committee reflects a growing concern in the community about the actions of certain members of that committee and their associates.
Ms McDonald presented her report on what was happening at Aratoi and a vision for the future, which she said had met with clear approval.
"We should now look forward to working co-operatively with a Friends committee that is committed to a constructive working relationship with the board," Ms McDonald said.
Although she attended Saturday's meeting, Ms McDonald is taking a break from the role of chair and has handed the reins to Frazer Mailman while she concludes a legal case in her role as a Queen's Counsel.