In 2003, there were 703 international pupils enrolled in Otago schools. That number dropped to 495 last year.
Nationally, the number has nearly halved, from 17,574 in 2003 to 8936 in 2012.
Although the 2003 figures represented the peak of international fee-paying pupil numbers in Otago during the past 15 years, Otago Secondary Principals' Association (OSPA) secretary Gordon Wilson said he was surprised by the steep downward trend.
He believed several factors had influenced the figures, such as
the global financial crisis, the Christchurch earthquakes and the Sars virus.
Many schools had recently made significant connections with overseas schools - particularly in Shanghai - and he believed these links would eventually bring more pupils to Otago.
OSPA immediate past president Brent Russell believed each international pupil contributed up to $30,000 to the local economy through school tuition, accommodation, school uniforms and school trips as well as personal spending. Parents of international fee-paying pupils who came to visit did the same through spending on flights, accommodation and other living expenses.
''International students have been bolstering the finances of secondary schools around the country for many years,'' Mr Russell said.
''If we didn't have them, our deficits would be even worse than what they are.''
Bayfield High School principal Judith Forbes said much of the money brought into her school by international fee-paying pupils was used to pay for extra staffing. But if IFP pupil numbers dropped too low, schools might not be able to provide extra teaching staff or extra learning opportunities for all pupils, because the Ministry of Education did not provide enough funding.
''It shouldn't be like that. International students should not be propping up the education system.''
She believed the pupils enrolled at Bayfield High School because they were treated as people, not simply sources of revenue. Despite the nationwide downward trend, Bayfield's IFP numbers remained high. Overseas parents, pupils and their agents ''shop around'' when choosing a foreign school for their children to attend, she said.
''You have to provide good homestays, excellent pastoral care, good academic results and a wide range of opportunities. They look in quite a lot of detail at each potential school, and each student that returns from a New Zealand school gives feedback to the agent.
''So, there is a massive level of word of mouth.''
