In NSW Public Schools numbers in Stage 1 were to be

20 for Kindergarten students
22 for Year 1 students
24 for Year 2 students.

This has been partially abandoned under the local schools, local decisions model as Principals will have more power to decide things like class size. I definitly think its important! I teach in a high school and the difference between even 25 and 30 is HUGE! If I was comparing schools and they were quite similar in values and "feel" , class size would be a big factor.