Michael Gove's education department failed to invite applications for a £500,000 grant to assist parents setting up free schools, before awarding it to his former adviser.

The New Schools Network, a charity and company run by the education secretary's former colleague, Rachel Wolf, 25, was awarded the grant by the Department for Education in June. No other organisation was asked to bid for the work, which was not publicly advertised.

The disclosure in documents released under the Freedom of Information Act could heighten some of the criticisms the new schools have attracted. The schools, which are independent of local authority control, will allow groups to create more autonomous schools with small class sizes, Gove argues, though critics say they could wreck social harmony by creating ethnic or religious enclaves.

The network – which is yet to receive the money – is at the heart of the plans for the schools which were inspired by US Charter schools and has a role in the application process.

Lisa Nandy, a Labour member of the Commons education select committee who has asked the Charity Commission to investigate the role of the New Schools Network, said that the role of Gove and his department must also be scrutinised.

"The question remains why they felt that a lobbying organisation that was set up specifically to promote the benefits of free schools and has been in existence for less than a year was best placed to provide impartial information to groups seeking advice," she said.

"The coalition insists they are cutting consultancy and quango costs and so, in this "age of austerity", why did they not see fit to deliver this service, which is in effect parroting their own policy, in-house?"

Nandy today received responses from Nick Gibb, the schools minister, who said: "Given the need for specialist skills and experience to be in place quickly it was decided to award a time-limited grant to New Schools Network."

Wolf, now 25, worked as a special adviser to Gove while he was shadow education secretary. The network, which describes itself as independent, was set up over a year ago. Mystery surrounds its other sources of funding because it has refused to reveal the names of anonymous donors.

In a response to a request from the pressure group The Other Taxpayers' Alliance, the Department for Education confirmed no other tenders had been sought.

It said: "[New Schools Network] has been active in this area for some time and was effectively the only organisation capable of providing the level of support needed by the number of interested parties quickly enough to enable the first free schools to open by September 2011."

But critics claim there were many other organisations equally well suited to offering advice. Fiona Millar, a campaigner for state-funded schools, said the Specialist Schools and Academies Trust, which is now 10 years old and oversees more than 5,000 schools, would have been ideally placed to bid.

The network's business plan which was used to apply for the grant, which was also released under a Freedom of Information request, has been heavily redacted and does not include any figures.

At least one of the events budgeted for in the business plan – a networking event which was supposed to happen in September – has not taken place.

Wolf's mother, a professor specialising in education's relationship with the labour market at King's College London, has been asked to review 14 to 19 vocational education for the department, while Wolf's father works for the Financial Times.

Rachel Wolf said the decision to offer the network a grant was made by the education department.

"There have been a number of other charities given grants by the Department for Education on precisely this basis without tendering, and for the same reason – that a programme was to be kickstarted and there was one obvious organisation to help," she said.

The network had not been able to meet some of its ambitions as outlined in its business plan – including events and the hiring of staff – because it still awaited the £500,000 grant. "We look forward to its arrival," she said.

A Charity Commission official said it is examining complaints from MPs and unions that the network should not be given charitable status because it is not independent. "Concerns have been raised about the independence of the New Schools Network. We contacted the trustees and are considering their response to determine whether there is any regulatory role for the commission," the official said.

A Department for Education spokesman said: "The New Schools Network is a charity and an established support group with a large existing network of groups interested in opening schools. At present they are the only organisation performing this role. That's why we believe they are best placed to help us build initial early momentum in this policy area.

"We believe this will provide a more personalised – and cost-effective – service for interested groups, and we will of course be monitoring the contribution of the New Schools Network constantly to ensure taxpayers are getting value for money."

• This article was amended on 28 October 2010. The original opening paragraph and heading said that Michael Gove's education department failed to invite bids for a £500,000 contract to assist parents setting up free schools. This has been corrected to conform to the rest of the article.