International students are spending longer studying at English language schools, boosting the schools' income even as student numbers fall.

Tuition and related fees at English language schools rose 17 percent to an estimated $142 million in the March year, Statistics New Zealand (SNZ) said today.

The information came from a survey of English language providers which also showed the number of students at English language schools fell 6.8 percent from the previous March year to 36,990.

The average course length rose to 12 weeks in the latest year, from 10 weeks previously.

The rise in spending on tuition and related fees was largely due to a $13m increase by students from Saudi Arabia, and a $7.5m rise from Chinese students.

Spending on English language tuition by Saudi Arabian students had risen every year, from $600,000 in the March 2003 year to $23m in the latest year, SNZ said.

Saudi Arabian students were now the third biggest spenders on tuition, replacing Japan, while China had pushed Korea out of first place.

While revenue from tuition and related fees had risen since the March 2006 year, it remained 44.9 percent below the peak of $258m in the March 2003 year, SNZ said.

An estimate for the total spending by international students studying at English language schools was up $41m to $284m in the March 2009 year, with revenue from accommodation up 22.7 percent.

The rise in spending by international students at English language schools was a bright spot in a gloomy picture for total income from international students.

When students at primary, secondary and tertiary level are added to the English language students, total estimated spending is put at $1.34 billion for the March 2009 year. That is down from $1.46b in the March 2008 year.