A senior United Nations official is examining the impact of changes to UK housing benefit on the human rights of low-income households.
Raquel Rolnik is meeting tenants across Britain affected by the shake-up.
Since April, social tenants in England, Scotland and Wales who are deemed to have surplus bedrooms have seen their housing benefit reduced.
Ministers say it tackles an unfair “spare room subsidy” but opponents have dubbed it a “bedroom tax”.
Ms Rolnik, the UN’s Special Rapporteur on housing, will outline the initial findings of her study next week after visiting London, Edinburgh, Glasgow, Belfast and Manchester.
Speaking midway through her visit, Ms Rolnik said: “The UK has voiced its commitment to human rights on repeated occasions, and this mission will give me an opportunity to assess in-depth to what extent adequate housing, as one central aspect of the right to an adequate standard of living, is at the core of this commitment.
“The UK faces a unique moment, when the challenge to promote and protect the right to adequate housing for all is on the agenda.
“In doing so, special attention would need to be given to responding to the specific situations of various population groups, in particular low-income households and other marginalised individuals and groups.”
The UK is a signatory to a number of international treaties which protect the right to adequate housing and non-discrimination.
Article 25 of the Universal Declaration of Human Rights includes housing as part of the “right to a standard of living adequate for the health and wellbeing of himself and of his family”.
Ms Rolnik’s final report will be presented to the UN Human Rights Council next year.
Ministers argue they are addressing an anomaly in the housing system where equivalent assistance in the social rented sector is not available to private tenants.
But critics claim it is forcing families into poverty and will increase the benefit bill by pushing people into the private sector.
A group of disabled people lost a legal challenge to the changes at the High Court in July, with judges ruling that the policy was not unlawfully discriminatory.
However, the High Court criticised the government for failing to follow a 2012 ruling that said housing benefit should not be cut where disabled children were involved.
Source: BBC News