Public finance watchdog chief Robert Chote has insisted that his Office for Budget Responsibility (OBR) resisted attempts from Treasury officials to change the wording of reports.
OBR chairman Mr Chote told MPs that his organisation was "robust" in its response to requests for changes and insisted "we write what we want".
The OBR was established by Chancellor George Osborne to provide independent economic and fiscal forecasts, which are published alongside his budgets and autumn statements.
The independence of the OBR means that the Treasury is only meant to intervene with the OBR if there is a factual inaccuracy.
However, emails published by The Times obtained under the Freedom of Information Act show officials appearing to overstep the rules by asking the OBR to alter "phrasing" in a report.
"It won't come as a surprise I'm sure, but we haven't strictly stuck to the 'factual changes only' requests so we're giving you our full download and suggestions," the Treasury wrote in an email, sent days before the chancellor's autumn statement last December.
"As usual, we would be very grateful if you could consider these and the phrasing around a lot of this."
Mr Chote told MPs at the Treasury Select Committee the OBR did not "fight shy" about using language which would displease the Treasury.
Referring to the December 2014 report, he said that "front and centre" in the executive summary was a reference to the scale of planned cuts in government spending.
"We referred to spending falling to its lowest share of GDP since the 1930s. I suspect that's not phraseology that the Chancellor would have chosen for himself."
Mr Chote added: "Similarly, I don't think they were very pleased with 'rollercoaster' as a description of the path of departmental expenditure limits in March. Some people suggested to me they felt that was inappropriate, I said I thought the language was necessary to create an impression to the wide audience of stakeholders."
Asked about The Times story, Mr Chote said: "Drawing a line between fact and interpretation is a difficult one to do. Personally, I'm relaxed about the idea if particular officials, in this case obviously we are dealing with a relatively junior official, want to offer us unsolicited drafting advice. I think we would be in a pretty weak state if we weren't able to be robust to that.
"Sometimes the things you get are sensible and useful, sometimes they aren't. At the end of the day, we write what we want. I think that the record shows that we don't fight shy of using phraseology that perhaps the Chancellor would rather we didn't."
Mr Chote, a former head of the Institute for Fiscal Studies (IFS), was appearing before MPs after being nominated to serve a second term as OBR chairman.
Underlining his independence, he said: "In 20 years as a journalist and at the IFS writing about Treasury policy, I have been treated to the 'we know where you live and you will never work in this town again' routine more times than I care to remember.
"It didn't affect me then, it wouldn't affect me now. If I was being put under serious pressure by the Chancellor, private offices, by senior officials, I would tell them to buzz off and I would tell you what was going on.
"But I'm not going to sit here and beat up on a hard-working grade six (civil servant) for having the temerity to offer us unsolicited drafting advice."
Mr Chote, a constituent of Labour's new leader Jeremy Corbyn, was asked about models to examine "radical" policies.
Labour MP John Mann asked him: "There may be more radical economic solutions floating around. There's going to be more pressure perhaps for people to look at what the majority of economists would conclude are the outcomes from those economic models."
Mr Chote stressed that the OBR was "constrained from looking at policy alternatives" and instead was focused on the Government's plans.
He joked: "As an Islington North resident, I am seized of the importance of considering radical options at all times - some of those things are easier to model than others."