Ms Lorck said she thought the increase had been "slow-burning", but that digital devices were really adding to the heat.
"Hawke's Bay parents are being asked to fork out huge amounts for digital devices at the beginning of the year," she said.
"If we make it too hard for these children and families to get these digital devices and get into technology, then they're so disadvantaged right from the beginning. It's creating a real equity issue."
Ms Lorck, who has a blended family of five daughters, said although the start of the school year was always challenging, it was hard for families to prepare because school costs were not in a lump sum. "Families do need to budget but the costs are increasingly so much, there needs to be facts and figures on the table for them to prepare.
"There's a lot of everyday costs that you don't really see adding up," she said.
ASG has also released predicted figures for the cost of education for a child starting school this year.
The difference between 2016 and 2021 costs reveals parents are expected to pay 8 per cent more to send their child to a state school.
The cost of a state-integrated education will rise 16 per cent, while the private school cost will increase by 21 per cent.
Giving a child 13 years of education at a state school beginning this year is predicted to cost $34,487, with the cost for state-integrated schooling at $90,383.
The cost of sending a child to a private school for 13 years is predicted to cost $270,066.
These figures include the estimated costs of school fees, transport, uniforms, computers, excursions and sporting trips.
Tukituki National MP Craig Foss said rising costs were always a concern, which is why the Government increased education funding every year.
"The start of the school year is a challenge for some families in the Bay, but the Government funds state schools to deliver a good Kiwi education at no charge to parents.
"Any parent worried about the cost of uniforms, stationery or other school equipment should talk to their children's school - they often have arrangements in place to assist families struggling financially."
He said the figures quoted did not bear any relation to the cost of educating children in Hawke's Bay.
"Parents can choose to buy top-of-the-line electronic devices, pay for after-school tuition and fund expensive trips, but they don't have to do so to ensure their kids get a good Kiwi education. Nor are they required to pay the voluntary donations ASG includes in its costings," said Mr Foss.
The state-integrated Lindisfarne College's consolidated 2016 fees for a "dayboy" was $8985. The consolidated fees for a full boarder was $19,880 and for a weekly boarder $19,480.
This total included attendance dues ($1840) and a voluntary parental contribution of $5300, amongst other expenses.
The state Napier Girls' High School accepts a voluntary donation of $170 for one student and $300 for two or more students.
This donation pays for internet costs, computer consumables, copyright fees, extra-curricular activities and additional capital expenditure as the school board may decide.
The figures have been criticised by the Ministry of Education.
The Ministry's deputy secretary for early learning and student achievement, Lisa Rodgers, said the Government paid the lion's share of education costs with donations making up a small part of school budgets overall.
"For every $1.80 parents donate to schools, taxpayers contribute about $100. It's important for parents to remember that any donations their school asks them for are voluntary.
"This year the Government will invest about $10.8 billion in early childhood, primary and secondary education."
She said operational funding for schools had risen more than $200 million since 2010.