The centre predicted that a total of Bt45 billion would be spent during the period when students return to school for the new semester.

The centre's survey also showed that one-third of the amount spent was likely to come from underground loans, because parents lacked adequate savings.

In a survey of 1,451 parents conducted from April 1-27, respondents said they would spend less than they did last year, due to rising oil prices, which limited their spending ability.

Of the total, Bt16 billion will be spent in Bangkok and the surrounding area.

Parents' spending can be divided into 40 per cent for tuition, 30 per cent for student uniforms and school kits, 13 per cent for food and 18 per cent for other expenses.

The survey also found that a high number of parents did not have enough to spend during the back-to-school season, with 35.2 per cent saying they would either have to seek a loan for the purpose, mainly from pyramid schemes and pawnshops, or work an extra job. In spite of the availability of education loans from financial institutions, the survey found parents preferred to loans from non-financial institutions.

Moreover, a large number of parents said they had to prepare a huge amount of cash for "tea money" entrance fees, which parents must pay to the school on top of the normal tuition fees.

Many parents also complained about the high amounts that they had to pay to get their children into good schools.

Makers of student products, meanwhile, must promote their goods more heavily to maintain their market share, because parents are facing budget constraints. They conduct department-store campaigns or bid to sale directly to students on campus.