The University of Canterbury's Student Association is staying tight lipped about an employment mistake that saw it cough up $15,000.

The Ministry of Business, Innovation and Employment found at least 14 UCSA staff members were not receiving sick and holiday leave because they were described as casual workers, when they were part time workers with an established roster.

Association president Sarah Platt wouldn't confirm whether the $15,000 in arrears was paid for out of student registration fees.

But says the mistake has been corrected, and staff backpaid.