The head of Immigration New Zealand has apologised to the international education industry for unacceptable delays in processing thousands of student visas.

Nigel Bickle said the recent backlog of 5500 applications was not good enough and plans were under way to ensure it did not happen again. Some students had been waiting up to five months without any word from the service about their permits.

Mr Bickle said he had assured Immigration Minister Jonathan Coleman that the backlog would be processed by the end of last month, and that had nearly happened, with all but 200 of the applications cleared.