More than 16,000 children from other provinces have swollen this year's pupil numbers, the Western Cape education department said on Friday.

Seventy mobile classrooms had been ordered this week to help cope with the influx, said education MEC Debbie Schäfer.

Almost 90% of the year-on-year growth in pupil numbers — which brings the total to 1,063,761 — was attributable to "in-migration from other provinces", she said.

"But the money does not follow the learners. The National Treasury has not responded adequately with financial adjustments to accommodate these learners."