Nearly 800 people were prevented from entering New Zealand over the past year.
The majority of those turned away at the border were rejected because of concerns over their character or because authorities were suspicious of their motives for entering the country.
The largest number of rejects fell under a programme especially targeting high-risk passengers who on some occasions were stopped even boarding their flight.
Figures released to the Herald under the Official Information Act showed 777 people were barred.
As in previous years, Malaysia had the biggest number of citizens stopped, 68. Immigration has put that down to how close the country is, but Malaysian Immigration has previously said the country was used as a transit point by syndicates which issue fake passports to help people enter countries that have visa-free arrangements with Malaysia.
An Immigration spokesman said a team based at Auckland International Airport targeted passengers believed to be high risk, by analysing information through airline reservation systems and Immigration's own intelligence, as people checked in for flights.
"When a high-risk passenger is identified, the risk-targeting team contact either Immigration, one of our international partners or airline ground staff to intercept the passenger. The travel document will be examined, and the passenger interviewed over the telephone. INZ staff will then decide whether or not the passenger can continue on their flight."
Those found not to be genuine can be stopped even before they board the plane.
Last year, New Zealand began using software from the United States that greatly enhanced Customs' ability to vet passengers - it can now do 102 million data sweeps a month and profile 65 flights a day.
In May, the head of Customs, Carolyn Tremain, told the Herald the software was "pioneering".
"Over 98 per cent of all travellers to New Zealand are legitimate travellers, and we really are looking for that needle in the haystack, and what this tool does is make that haystack smaller in terms of the hay and make it easier for us to apply the resource to find the needles," she said.
Some of the things they look for are whether the traveller has imported illicit goods in the past, has previously come to Customs' attention, or has booked a flight suddenly.
Anyone who applied for a visa to come to New Zealand had to be of good character and not pose a threat to the country's security.
Those people rejected mainly came from countries which had visa-free status with New Zealand and were considered likely to work unlawfully or become overstayers.
"People who arrive at the border having been profiled as meeting an element of immigration risk are interviewed to determine their bona fides. The decision to refuse entry can be based on, among other things, their immigration history, the immigration history of any family members, the information they provide at the interview and intelligence we may have from other agencies or countries," the spokesman said.
However, Immigration would not give specific details of what they looked for "for operational security".
Staff also worked closely with other border protection agencies such as Customs and the Ministry for Primary Industries (MPI) at international airports.
"Customs and MPI officers often uncover items in a passenger's luggage indicating the passenger is here to work illegally.
"This information assists [us] to determine whether the person should be allowed to enter New Zealand."
Earlier this year, 41-year-old Christian Dario Alcalde exposed a legal loophole when he travelled to and from the country on false passports. As a citizen of Australia, he had permanent resident status here, but when his Australian passport was revoked he was still able to travel on it on a flight from Auckland to Bangkok.
The case has highlighted a border-control loophole in which someone can use a revoked foreign passport unless New Zealand authorities have been formally notified.
However, efforts were under way to strengthen Immigration's work with international agencies, especially to identify those attempting identity fraud.
Part of that was through the development of the biometric programme, the department said.
"This includes the introduction of advanced passport readers which can authenticate passports and capture passport images of people travelling here.
"In the future, face recognition biometrics will be able to use these photos to run matches against people subject to Immigration alerts," the spokesman said.
By the numbers
• 777 people refused entry into New Zealand from July 2012 to June 2013, 226 females, and 551 males.
• 646 refused entry at Auckland International Airport.
• 447 refused entry because they had non-genuine reasons for being in New Zealand.