OUSA voted to quit New Zealand Union of Students' Associations (NZUSA) saying it felt the organisation did not provide value for money for the $45,000 it was paid a year.
NZUSA president Daniel Haines said yesterday OUSA's decision to quit came out of the blue.
''If they had concerns I wish they would have spoken to us about it, because as far as I knew everything was fine,'' Mr Haines said.
He did not accept the view NZUSA did not achieve enough gains for students and said OUSA risked becoming ''isolated'' by no longer being part of the national body.
This was because NZUSA, by being able to represent the whole New Zealand student body, was in a better position to speak to national organisations.
He hoped OUSA would reconsider its move.
Acting OUSA president Ryan Edgar said it was time to look at a new model of national representation.
''National student representation discussion typically focuses on fixing NZUSA, rather than discussing alternative models.
''OUSA has decided to withdraw in order to allow students to engage in a discussion about how to best represent students, rather than being tied to the past,'' Mr Edgar said.
OUSA finance officer and president elect Paul Hunt ''completely'' disagreed with the suggestion it would be left isolated, saying it had a good record of representing students, which included submitting to Government select committees.
He accepted there was a benefit from having a national student body, but felt a ''totally different'' model was needed.
''We think there are structural issues which hinder NZUSA's capacity to be an effective representative for students.''
OUSA had long been concerned about the state of NZUSA, so its decision should not have come as a surprise.
Because of a requirement for a 12-month notice period for withdrawal in the NZUSA constitution, OUSA would still pay its $45,000 membership next year.
