Northern Ireland's Education Minister John O'Dowd has once again been urged to intervene to help reduce school uniform prices.
Parents have complained that restrictions – such as having to wear certain brands or only being able to buy items in specific shops – have led to costs going through the roof.
The renewed criticism comes after it emerged that the average bill for equipping a child for school has doubled since the 1980s to over £550.
And it follows last year's furore over the price of uniforms after it emerged that a blazer costs up to £100 while sports kits can hit £150 or more.
Sinn Fein MLA Chris Hazzard, who sits on the education committee, told the Belfast Telegraph he has just tabled a private members' bill on school uniforms.
"We need to address the sales monopoly because lower income families are finding prices increasingly prohibitive," Mr Hazzard said.
The minister said he recognised that the cost of school uniforms can place a burden on families in the current economic climate.
And he said he had responded by allocating additional funding for school uniform grant.
"This year my department allocated over £4m to help the families of almost 78,000 children with the cost of school uniforms – a rise from the 27,800 in 2006-7," Mr O'Dowd (below) said.
"I have also encouraged schools to work proactively to reduce restrictions and introduce more competition in the supply of school uniforms.
"There is an onus on schools to help parents and I consider it wholly unacceptable that some schools charge excessive costs."
The department issued guidance to schools in March 2011 on school uniform policy and the minister also wrote to all schools in September 2012 reminding boards of governors of their responsibilities.
It said the guidance makes it clear that the department expects boards of governors to give high priority to cost considerations when designing their uniforms.
Mr O'Dowd added: "Clearly if schools give parents greater choice over where to buy uniform items this will drive competition and bring down the prices that parents pay."
Lynda Wilson of Barnardo's Northern Ireland said the cost of new school uniforms was an ongoing pressure, especially when parents have more than one uniform to buy.
"While the school uniform grant helps some families, for those who fall just above the threshold it is a very expensive time and a constant worry," she said.
"Back to school includes school shoes, school bags, stationery and sports equipment and the costs quickly mount up."
Ms Wilson said parents are often prohibited from sourcing uniforms from cheaper shops because many schools opt for brands.
"Parents are also under pressure from their children to provide the cool shoes and the cool bag," she said.
"Buying school uniforms comes at the end of the summer which is already an expensive time for parents and it is a cost which cannot be avoided or spread out."
She added: "In 2009 Barnardo's carried out a year-long study, Below the Breadline, which followed 16 families living in poverty and paying for school uniforms was identified as a constant worry.
"One child told how a friend gave him £10 for his 14th birthday and he gave it to his mother to help towards the cost of uniforms."