Enrollment numbers have swelled at many of Sydney's more exclusive public schools.

Enrollment numbers have swelled at many of Sydney's more exclusive public schools. Photo: Anthony Johnson

Parents are so desperate to enrol their children in public primary schools with impressive results or in popular areas that they have resorted to extreme measures such as producing fraudulent documents to claim they live within the school's boundaries.

Some of Sydney's top performing schools have swelled to more than 1000 students and others in areas that have had a recent baby boom have doubled in size in just four years, prompting concerns from parents and education experts about overcrowding and a loss of community in schools.

The latest enrolment data from the NSW Department of Education and Communities shows some primary schools in the eastern suburbs, including Vaucluse and Maroubra Bay, have doubled their student numbers since 2010.

At Vaucluse Public School student numbers have doubled to 301 while at Maroubra Bay the student population has increased from 133 to 261. High achieving schools such as Matthew Pearce in Baulkham Hills are now well beyond capacity at 1184 students. In the inner west, Orange Grove Public School has seen its population increase by 83 per cent to 343 students since 2010.

Many of Sydney's most popular schools in the inner west and lower north shore are so full that principals refuse to accept out-of-area enrolments, even if siblings are already at the school, and insist that parents produce several pieces of original identification with a current address before a child is enrolled.

But despite the strict rules around enrolments, and warnings from schools about the severe penalties for making false claims about addresses, parents are increasingly finding ways to secure a spot at their school of choice.

The Sun-Herald knows of one example of a mother swearing a false statutory declaration about her address to enrol her child in a popular eastern suburbs school while online parenting forums are littered with tips for rorting the enrolment rules, including "borrowing" a stranger's address.

Parents use the addresses of family members to claim they live in the catchment of a school, while real estate agents in sought-after areas say they are swamped with rental applications in January as families try to secure an address in the area.

Oliver Dunstan, from Laing and Simmons in Woollahra, said his agency was leasing 30 properties a month in January and February, many to families wanting "their name on a lease" to get into Woollahra Public.

Woollahra is so full, with 700 students, that its principal has asked the Department of Education to redraw its catchment boundaries to reduce the student population.

Similar schools with good NAPLAN results, including Artarmon, Neutral Bay and Chatswood, which also have selective opportunity classes, are bursting at the seams.

But one parent from Artarmon Public School, which has almost 1000 students this year, said she was "very confident" some of the students were not locals.

''It seems a new demountable is going up almost every term at the expense of play equipment and space to run around, which I think is as critical as sitting in a classroom learning," she said.

Trevor Cobbold, the national convenor of the public education group Save Our Schools, said there were several problems with oversized primary schools.

He said research showed small primary schools performed better than larger schools, although the difference was less pronounced in very socially advantaged areas.

But Mr Cobbold also warned that primary schools could become ''highly socially segregated'' if parents favoured certain schools over their local option.

''School is not just about student achievement; it is about being active, developing gross motor skills and kids learning to get on together,'' he said.

''Parents can be misled about the quality of a school and they end up chasing their own peer groups.''

Chris Bonnor, co-author of What Makes a Good School and a former principal, said parents should not rely on NAPLAN results on the MySchool website when deciding which school to send their child.

"You could train any monkey to train other monkeys to go into a school and raise the NAPLAN scores,'' Mr Bonnor said.

A spokesman for the Department of Education said it had several strategies to manage capacity issues, including building new schools, changing catchments and providing demountables.

''Where possible, the department constructs multistorey accommodation to reduce the impact on a school's play space. It also aims to position demountable accommodation to minimise any loss of play areas,'' he said.

The spokesman said that once a student was enrolled in a public school, they remained enrolled in that school even if their address changed.

But if it was later found that an enrolment in a public school was based on false information, the decision to accept that enrolment could be reversed, he said.