Education Minister Hekia Parata says a mailing error which led to 455 NCEA exam papers being sent to the wrong students was a "regrettable mistake".
She told Parliament this afternoon that the New Zealand Qualifications Authority (NZQA) had apologised for the blunder.
"In the context of our 161,000 students having their 1.1 million scripts returned - something which only New Zealand does - there was a mailing error affecting the return of scripts to 455 students.
"While it is a regrettable mistake, and it is the first time there has been a sorting and mailing error of this kind, the chief executive of NZQA has apologised and assured me that future quality checks have been put in place."
Ms Parata knew about the lost papers in January but was not aware of the scope of the mistake until yesterday [MON].