Helensburgh residents had been concerned their children would have to go to Heathcote High, which is closer to Helensburgh and is the suburb's designated high school.

This upset some members of the Helensburgh Public community, who were worried siblings may be separated or students may not be able to go to their chosen school.

On Thursday it was "confirmed" that any students who are enrolled at Helensburgh PS - and their siblings - would be given an exemption so they can choose either Heathcote or Bulli for high school, as had been the case for decades.

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This applies only to students currently enrolled. In future years Helensburgh students who apply to enrol at Bulli will be assessed as non-local applicants.

Member for Heathcote Lee Evans took credit for the clarification.

He said there was a "unique context around the three schools".

"Heathcote High School remains the designated high school for Helensburgh families, however, offering this choice will support existing school families who have had an expectation of being able to choose either of the high schools," Mr Evans said.

Heathcote High is 17.6km from Helensburgh post office. By train it's a 12-minute ride plus a five-minute walk.

Bulli High is 22.5km from Helensburgh. By train it's a 37-minute ride plus a five-minute walk.

But families with work or other commitments in the Wollongong area would find the travel south a better fit than Heathcote.

"When I heard of the concerns at Helensburgh, I met with [Education] Minister [Sarah] Mitchell to ensure families in our region were given choice and flexibility when it comes to the Department of Education's enrolment policy," Mr Evans said.

"I am absolutely committed to making life easier for families and parents in our electorate; and I am happy to fight in Parliament for solutions to issues that face our community."

The Department is trying to reduce "school shopping" after figures showed more than 40 per cent of students in Sydney went to an out-of-area high school.