Tory ministers reportedly insisted on rewriting a government report on immigration because they believed it was too pro-European.
A leaked copy of the report, which was rewritten twice, concluded that migration from the European Union had a "largely positive" effect, although it acknowledged there was "less agreement" about the impact of low-skilled foreigners coming to the UK.
Home Secretary Theresa May's department was accused by Liberal Democrat Business Secretary Vince Cable of being "propagandist" in the changes it made to the report.
The report was due out in December but was delayed due to the coalition row about its contents and publication was postponed again in the spring until after the European elections in May, according to BBC's Newsnight.
The programme, which obtained the leaked document, said the report pulled together evidence on the impact of immigration from EU countries, particularly in the period following the enlargement to cover former eastern bloc countries in 2004.
It quotes estimates that suggest there are 2.3 million Europeans living in the UK - and up to 2.2 million British citizens living in Europe.
The report's executive summary says: "The impact of the labour market is considered across a range of different sectors, including manufacturing, engineering, legal services, agriculture, hospitality, financial service and health care; and with regards to highly skilled, low skilled and regulated professions.
"The effects are viewed as largely positive, providing a wide range of skilled labour and opportunities for UK workers and their employers in other member states."
But there is "less agreement regarding low-skilled migration".
Mr Cable, who has repeatedly clashed with Mrs May about immigration policy, told Newsnight about his concerns following the changes to the report's initial draft.
"We disagreed with the content and thought it was propagandist rather than objective which is why we went back to the drawing board," he said.
"A study has now been produced that is balanced."
A Home Office spokesman said: "We do not comment on leaked documents. The balance of competences report on free movement of persons will be published shortly."