Parents are being asked to fork out as much as $1000 for primary school camps and excursions, prompting concerns children from poorer homes could be priced out of school trips.

A survey of the cost of excursions and camps from more than 20 primary and high schools across Sydney shows a variety in the price and scale, from $250 to $1100.

Year 6 students from Lindfield Public School went away for five nights in August at a cost of $1100 per student, with two nights in Canberra and three nights at a ski lodge in Jindabyne, including ski lessons, equipment hire and lift pass.

A five-night camp for Mosman High School's Year 9 students was billed at $924, covering accommodation, a three-day ski lift pass, equipment hire and daily ski lessons.

NSW Primary Principals' Association president Geoff Scott said the cost of excursions had shot up in recent years and it was not uncommon for week-long camps to cost more than $1000.

"Affordability is a factor schools always have to take into account and many schools put aside funds to assist students who would struggle to meet the costs," he said.

Public education advocate and retired principal Chris Bonnor said it was often schools in middle-income communities that had the greatest trouble with parental affordability.

"It's not the schools in very well-off areas and it's often not the schools in disadvantaged areas that find this dilemma," he said. "It's the schools in the middle where parents are not wealthy but there's no targeted funding, so schools can't draw on any other money and they do not have any disposable cash."

While schools regularly offer financial help, for parents the guilt attached to not sending their child along with their friends can put great pressure on family budgets.

David Jordan is chairman of the Voluntary Parents Services Co-operative, which represents the parents of 13 public schools, predominantly on the north shore.

"Just because people live in this area doesn't necessarily mean they are wealthy and a lot of the wealthier parents send their kids to the private schools," he said. "A lot of people are struggling; they might be divorced mothers or have a sick family member."

While some camps hit the $1000 mark, he said most cost between $300 and $500.

In a letter outlining a $330 two-night camp to Jenolan Caves, Bathurst and Hill End last year, parents at Loftus Public School were told the costs of excursions had "risen sharply over the years due to increased insurance, fuel price rises, seat-belted coaches, etc but the educational and social benefits make for our students these trips 'priceless' and provide many lasting memories".

Parents at Bankstown North Public School have been asked to pay $390 for a four-night camp to Broken Bay Sport and Recreation Centre next month, while year 6 students at Woolooware Public School will go on a $360 trip to a recreation camp at Lake Macquarie for four nights.

Mr Bonnor said school camps were important avenues for building deep relationships between students and with teachers.

"But do you have to go skiing to do that or can you go down to Little Wobby on the Hawkesbury River for two nights for a fraction of the cost?" he said.

The NSW Department of Education said while excursion costs were determined at the school level, there should be no undue financial burden imposed on families.

"Where financial hardship is understood to be the reason for a student's non-participation, schools must endeavour to provide financial assistance," the spokesman said.

"Unless exceptional circumstances exist, all students should have the opportunity to participate in an excursion. Where a student cannot participate in an excursion, alternate activities must be available that provide for similar learning outcomes, particularly where an assessment task relates to the excursion."