A coalition of leading charities has urged Labour to introduce new rental laws which will ensure poorer tenants are not “filtered out” of the housing market.

Unfair guarantor rules are allowing landlords to discriminate against “undesirable” tenants, they say, and should be changed as part of Labour’s upcoming renters bill.

Research from Shelter has found that one in three renters who are asked for a guarantor struggle to provide one, meaning around 600,000 renters have struggled to secure a home in recent years.

In an open letter to housing secretary Angela Rayner, 28 organisations including Shelter and the Joseph Rowntree Foundation say that this issue will only grow worse if not brought in alongside other anti-discrimination measures set to come into effect as part of the bill.

This is because landlords, “will simply switch to further abusing their power to request a guarantor, even when there is very little danger that a tenant will not pay rent,” the letter said.

Co-ordinated by the Renters’ Reform Coalition, the letter asks the deputy prime minister to make an amendment to the Renters’ Rights Bill, currently being considered by the House of Lords, which she is spearheading.

The signatories do not call on the government to scrap guarantors entirely. Instead they ask Labour rules out demands for a guarantor where tenants income is sufficient to cover the rent, or where the landlord has insurance to cover any non-payment, and limit guarantor liability to six months’ rent.

If unchanged, these rules are likely to become more discriminatory against “poorer tenants and those in receipt of benefits,” they write, as they will be “less likely to be in a position to know a high-earning homeowner well enough for them to offer to guarantee rent”

Kelly, 41, a mother-of three from Leeds, currently lives in a home with severe damp and mould issues which have been exacerbating her family’s medical problems.

She is looking to move, but has found it impossible due to letting agents insisting she must have a guarantor who earns at least £38,000. This is despite her having enough income, with her housing benefit, to cover rents in her area.

She said: “Even though I could afford the rent, guarantor requests have repeatedly stopped me from renting a home as I am not in a position to appoint someone earning that sort of money.

“I feel like this is discrimination against people who receive housing allowance. Why shouldn’t I be able to find a home like everyone else?”

Sean, 55, from Glasgow, recently faced a similar experience. Despite working as a senior copywriter and earning up to £50,000 a year, he was rejected from multiple rental properties in Newcastle, Coventry and Birmingham as his required guarantor, his 80-year-old mother, was a pensioner.

This happened to Sean six times in six months, he says. The situation left him with no choice but to rent Airbnbs and sleep on friends’ couches until he was finally able to find a spare room with a relative.

Sean said:”I had a good job, well paid and with three months’ worth of bank statements and I was refused rental(s), owing to my required guarantor being a pensioner.

“Other letting agents wanted six months’ rent up front, three years’ worth of bank statements (which my bank refuses on security grounds and I agree) AND a guarantor (again, refused on age grounds, my mother being a pensioner).”

Dan Wilson Craw, Deputy Chief Executive of Generation Rent, said: “Everyone needs a safe, secure, and affordable home. Unfortunately, many tenants face discrimination from landlords when searching for a place to live. Even if you can afford the rent, if you’re self-employed or relying on benefits, landlords can demand multiple months’ rent upfront, or that you get a homeowner to guarantee your rent.

“While the Government’s move to limit rent in advance is a positive step towards ending discrimination while renting, it will continue through excessive guarantor demands. The Government must act to close this loophole. If you can afford the rent, there should be no need for a guarantor.”

Labour MP for Leeds Central and Headingley Alex Sobel introduced an amendment during an earlier stage of the bill which would have prevented landlords from requiring a guarantor providing a tenant could pass an affordability check, but this was not voted on.

Addressing the amendment, housing minister Matthew Pennycock said there was a “strong case”, adding: “I appreciate fully that obtaining a guarantor can be difficult for some prospective tenants, and I understand the reasoning behind his amendment.

“However, I am also mindful that in some instances the use of guarantors can provide good landlords with the assurance necessary to let their properties to tenants who may otherwise find it difficult to access private rented accommodation.”

The minister concluded that the matter remains “under review” and that there will be more discussion on it in “the weeks and months to come.”

A Ministry for Housing, Communities and Local Government spokesperson said: “We have no plans to restrict the use of guarantors, but we are clear landlords should not discriminate against any prospective tenants and consider them on a case-by-case basis.

“Our Renters’ Rights Bill will create a fairer housing market by stopping landlords from demanding large amounts of rent in advance, while the reforms will further strengthen tenant rights and protections by abolishing section no fault 21 evictions, empowering tenants to challenge excessive rent hikes, and ending unfair bidding wars.”