On Tuesday, the president of the Association of Registered Hairdressers, Ria Bond, emailed the department urging it to review those findings.
Ms Bond said she feared the inspectors lacked knowledge about industry practices.
"I told them they had sent a really bad message out there to the industry. You don't need to lose an arm and a leg to have serious harm."
Her organisation fields on average of four consumer complaints a year. "[Hair Co and Beauty Co] have had at least four complaints since May. That's abnormal."
Ms Bond said her association had long called on the Government to regulate the industry to ensure that each salon had at least one qualified hairdresser.
Joseph Brooks, whose management firm is responsible for the staff of Hair Co and Beauty Co, blamed Ms O'Callaghan's injuries on an ex-employee.
But a couple who bought a salon off Mr Brooks said products were two years expired - an accusation he denied. They have asked not to be identified.
Ramona "Liz" Jungwirth is now director of Hair Co New Zealand after Mr Brooks' directorship ceased in April last year.
Joseph Ronnie Brooks was declared bankrupt by creditor petition to the High Court at Christchurch on June 28, 2010.
He strenuously denied being bankrupt when contacted by the Herald.
But James Cowles, director of plumbers Clyne & Bennie 1998, the petitioner behind the bankruptcy, confirmed Mr Brooks owed his company $34,759.
The amount was for plumbing work at new Hair Co and Beauty Co salons in Westfield Riccarton Mall in Christchurch.
A liquidators' report by PricewaterhouseCoopers into Hairstyle Management Eastgate - an associated company of Hair Co - also confirmed that Mr Brooks, its former director, had been made bankrupt.
PwC partner Malcolm Harris said liquidators considered Ms Jungwirth to be a director of the company by virtue of her apparent high-level managerial involvement.
The Companies Office register lists Mr Brooks as the director of eight companies, director or ceased director of three companies in liquidation and ceased director of six companies.
Ms Jungwirth is listed as director of three other companies, including one for which Mr Brooks is a ceased director, only under a different spelling of her first name - "Romana".