Key Points:

More than 400 foreign students have sent packing in the past four years for crimes or indiscretions, costing the taxpayer around $750,000.

Nearly 300 of the students required police escorts back to their home countries after being assessed as security or safety risks, according to figures released to The Dominion Post under the Official Information Act.

Some of the foreigners - mostly from China, India and South Korea - had breached permit conditions by trying to use degrees and other education certificates with fake details or from institutions they never attended.

Others worked illegally, dropped out of courses or committed crimes, such as driving, drug and firearms offences.

The Labour Department said the number of forcible removals each year was relatively small, and the cost should be balanced against money pumped into the economy by thousands of foreign students.

Forcibly removed students were banned from the country for five years and had to repay removal costs before being allowed back, but many never return and much of the costs was outstanding.

The New Zealand Qualifications Authority has caught 211 foreigners trying to use forged qualifications since 2002.

Some cases were referred to the Immigration Fraud Service, Interpol and police.