Education Secretary Ruth Kelly has denied the government is "bullying" Labour MPs over plans to make England's state schools more independent.
Ms Kelly said talking to colleagues was not bullying
Her comments come after Martin Salter resigned as a parliamentary private secretary, saying he could not "be part" of such "a government operation".
Ms Kelly said: "I don't think talking to my colleagues and explaining policy to them and listening is bullying."
"I don't really understand why he's resigned," she told the BBC.
'Concerns and reservations'
Mr Salter, MP for Reading West, resigned as parliamentary private secretary to Schools Minister Jacqui Smith on Wednesday.
He said he shared the "concerns" and "reservations" of many in the party over the education white paper, published last month.
Under the plans, part of Tony Blair's reform agenda, schools would gain more independence from local authorities and could become "trust schools".
This would give them more control over finances, staff and pupil admissions.
Some Labour MPs fear this will mean a return to widespread selection by ability.
But Ms Kelly said this was a myth, as the arrangements would be "within the admissions code that ensures fair admissions".
Mr Salter said he had no wish to "embarrass" anyone but was concerned by some of the reforms.
"In particular, I am worried that the proposals could lead to pupils from poorer areas being disadvantaged as popular schools expand, and wealthier and better-informed parents are able to set up their own schools," he said.
"I also believe that local education policy should remain democratically accountable, which is why I have problems with plans to downgrade elected LEAs."
Mr Salter said he wanted to be free to work with other Labour colleagues on education proposals that would unite the party.
"There is also a conflict of interests with my role as a member of Labour's parliamentary committee, where I am expected to reflect the concerns of my colleagues," he said.
Ms Kelly told BBC Radio 4's Today programme it was "unprecedented" for the MP to be both a government aide and a member of Labour's parliamentary committee.
She defended the drive to promote the white paper.
"I don't think talking to my colleagues and explaining policy to them and listening is bullying," she said.
"I think it's a really good way of policy-making."
Liberal Democrat education spokesman Ed Davey called Mr Salter's resignation "a major blow to the Kelly charm offensive", adding that the government could face a "major defeat" over the school plans.
The proposals are to form the basis of an Education Bill early in the New Year.