The charity runs a scheme which helps secure loans and grants for refugees to help them pay deposits and costs associated with moving.
A report by the charity found almost all (98 per cent) refugees referred to its scheme were completely homeless.
Less than half (48 per cent) of the 160 refugees polled were able to access a private tenancy through the scheme, even with specialist support that it provides, between November 2018 and October 2020.
This rose to almost two thirds (62 per cent) for new refugees using the service during the coronavirus pandemic.
Refugees, including those fleeing from war-torn countries, are served with an eviction notice from the Home Office as soon as they earn the legal right to stay in the UK.
Chief executive of the Refugee Council, Enver Solomon, said: “It’s a tragedy that one of the first documents newly-recognised refugees receive is an eviction notice.
“London is a wealthy and cosmopolitan city, full of opportunities, yet for too many refugees their welcome is blighted by an imminent threat of homelessness.”
One of the main issues for refugees is that they are not allowed to work while their claim is being processed by the Home Office meaning they cannot afford hefty deposits in inner cities.
The charity is calling on Mayor of London Sadiq Khan - as well as the other candidates in next week’s mayoral race - to commit to a fund to help refugees pay the eye-watering deposits on private housing in the capital.
Adonis Magema, who coordinates the council’s private rented sector project, told the Standard: “How can refugees pay a housing deposit when they arrive with nothing and are banned from working?
“It breaks my heart to see refugees go from the joy of receiving their status to facing the terrifying prospect of sleeping rough within a matter of days.”
A refugee called Emmanuel said: “You get your status and you’re excited that you can get on with your life, but then, you get another knock.
“You have no resources to be independent, no foundation. I only had 28 days to find somewhere, it was impossible. I ended up in a hostel.
“I applied to around 40 landlords, but nobody gave me a chance, they all rejected me. I felt like I was in the middle of the sea, trying to get to shore.”
He was eventually helped into accommodation without having to pay a deposit by the charity’s scheme.
As well as setting up a fund to help refugees with their deposits, the charity is calling on London mayoral candidates to provide pre-tenancy training for landlords and work closer with local authorities.
In London, only three councils said they had supported refugees via the private rented scheme in the past year. In those cases, the numbers of refugees helped was 30, five, and three.
Mr Magema added: “It’s a terrible situation for refugees when they find themselves in this position but a solution is relatively simple and low-cost.”