A United Nations report on UK housing conditions calling for the suspension of the bedroom tax has been dismissed by the government as partisan, discredited and a "misleading Marxist diatribe".

The full report by the UN's special investigator on housing, Raquel Rolnik, who made a research trip to Britain last August and September to look at housing provision, was published by the UN on Monday.

In it, Rolnik reiterated her earlier call for the bedroom tax policy to be suspended and reviewed because it negatively "impacts on the right to adequate housing and general wellbeing of many vulnerable individuals and households".

The report said lack of investment in housing over several decades meant Britain now faces a crisis of housing affordability and availability. It called for increased protections for tenants in the rapidly growing private rented sector who find themselves with "very few rights and little security", and called for a series of welfare reforms to be re-assessed to ensure they do not impact disproportionately on the most vulnerable individuals.

Britain's previously good record on housing was being eroded by a failure to provide sufficient quantities of affordable and social housing, the report said, with the result that "the structural shape of the housing sector has changed to the detriment of the most vulnerable". It called on the UK government to invest more in social housing.

The report did not hold back from documenting the combined impact of welfare reform and the housing crisis on vulnerable people, which Rolnik found on her visit had left many low income, disabled and homeless people in "tremendous despair".

The report's formal publication triggered an instantly defensive response from the government. Two departments reacted with unusually strongly-worded dismissals of the UN research document.

Housing minister Kris Hopkins said: "This partisan report is completely discredited, and it is disappointing that the United Nations has allowed itself to be associated with a misleading Marxist diatribe."

A spokeswoman at the Department for Work and Pensions was disparaging about the research undertaken by the UN rapporteur during her 12-day trip last year.

"This report is based on anecdotal evidence and the conclusion was clearly written before any research was actually completed," she said.

Rolnik said she would not be making any further comment on the report or her findings until the report is discussed with the Human Rights Council in New York on 10 March.

A former urban planning minister in Brazil, Rolnik met dozens of council house tenants during her visit last year, when – at the formal invitation of the UK government – she travelled to Belfast, Manchester, Glasgow, Edinburgh and London and visited council estates, food banks, homelessness crisis centres, Traveller sites and new housing association developments. She also reviewed hundreds of written testimonies.

Her report described the impact of bedroom tax on low-income tenants who "faced hard choices between food, heating or paying the rent" as they struggled to stay in the house they had lived in all their lives. It said: "Many felt targeted and forced to give up their neighbourhoods, their carers and their safety net."

The report added: "While in principle the [bedroom tax] policy does not force people to move, the reality of people's experience, many of whom are working people with no income to spare, left no doubt in the special rapporteur's mind that many have no other option, which has left them in tremendous despair."

Prof Aoife Nolan, a human rights law expert, told the Guardian that despite the UK being party to the UN covenant on economic, social and cultural rights the government would not be forced to act on the findings of the report.

"There is no world human rights police that will come in and assume control of UK housing policy. But we will definitely see the report being used as an advocacy tool by groups seeking more effective protection of the right to adequate housing in the UK."

She added: "The special rapporteur is not putting forward an alternative 'Marxist' vision – she is simply highlighting where current government policies are not compliant with the international human rights standards that it voluntarily signed up to. Putting the housing rights of the most vulnerable and marginalised at the heart of national housing policy is not 'Marxist'; it is simply what any decent society should be trying to do."

Shadow housing minister Emma Reynolds said: "Labour has called on David Cameron to reverse his unfair and unworkable bedroom tax because we can see the impact it is having on hard-pressed and often vulnerable people, the majority of whom are disabled. If he doesn't repeal the bedroom tax, the next Labour government will."

Rolnik has spent much of her five-year tenure as the UN's unpaid special rapporteur on adequate housing looking at human rights violations in countries including Rwanda and Kazakhstan.

Appointed by the UN human rights council, the former minister with the centre-left Workers' party spent the previous mission last year looking at slum housing in Indonesia. She said Britain's housing crisis was an equally urgent subject for investigation.

Rolnik's initial comments triggered an equally savage response from the Tories when she first made them.

The Conservative party chairman, Grant Shapps, dismissed her as "a woman from Brazil" and wrote a letter of complaint to the UN secretary-general, Ban Ki-moon, calling her proposals "an absolute disgrace". A junior UN official was deputed to respond to the complaint, and defended both Rolnik's appointment and her visit.

"Ms Raquel Rolnik is one of 72 independent experts appointed by the United Nations Human Rights Council – the lead UN body responsible for human rights – on the basis of their expertise and independence, and following a competitive selection process", the official stated in a letter, adding that her trip was "planned and organised over many months in consultation with the government" and complied with necessary UN rules and procedures.

The government continued to attempt to undermine her publication by disputing whether she was formally invited to undertake an investigation here.

But Rolnik pointedly states in the first line of her report: "At the invitation of the central government, the special rapporteur on adequate housing as a component of the right to an adequate standard of living, and on the right to non-discrimination in this context, undertook an official visit to the United Kingdom of Great Britain and Northern Ireland from 29 August to 11 September 2013."