Shabana Mahmood’s decision to tell every person applying for asylum from Monday that their status is temporary could undermine the refugee convention, the Law Society has said.

The body representing solicitors in England and Wales said the home secretary’s move to review every refugee’s status after 30 months was “in tension” with the UK’s legal obligations.

Keir Starmer’s government is preparing to announce a series of hardline policies that are meant to deter people from travelling to the UK to claim asylum.

Mahmood, who is closely associated with the Blue Labour wing of her party, has faced a backlash from MPs, peers and affiliated unions for pressing on with the policies after Labour came third in last week’s Gorton and Denton byelection.

From Monday, refugees will need to get renewed permission to stay or apply for a visa route like any other authorised immigrant, including paying associated fees. The policy shift is modelled on Denmark’s strict system.

The Law Society of England and Wales’s president, Mark Evans, said: “The rules announced today will create prolonged uncertainty for people who want to live free from danger and have been recognised by the government as needing protection.

“The changes stand in tension with article 34 of the refugee convention, under which the UK has agreed to facilitate as far as possible the assimilation and naturalisation of refugees.”

Article 34 of the convention, which was signed by the UK in 1951, reads: “The contracting states shall as far as possible facilitate the assimilation and naturalisation of refugees.

“They shall in particular make every effort to expedite naturalisation proceedings and to reduce as far as possible the charges and costs of such proceedings.”

Organisations working closely with refugees have expressed concern at the proposals, saying they will re-traumatise people who have come to the UK from war zones and suffered torture.

Sophie McCann, the forced displacement and protection advocacy adviser at Médecins Sans Frontières UK, said the decision was “another cruel development that will harm people who have fled the horrors of conflict, violence and persecution”.

She added: “Embedding prolonged uncertainty and fear within the asylum system will create further psychological harm and inhibit refugees’ – including our patients’ – ability to heal from their experiences and rebuild their lives with dignity.”

Natasha Tsangarides, an associate director at Freedom from Torture, said: “This policy change will affect men, women and children who have been recognised by our government as needing protection from torture and war.

“They have fled countries like Iran and Sudan for standing up for the same freedoms we cherish in Britain.

“A grant of refugee status should be a moment of celebration – a gateway to a new life and the chance to put the horrors they have endured behind them. Now, they will have to relive that trauma every 30 months.”

A Home Office spokesperson said: “We will always provide sanctuary to those fleeing war and persecution, but we must also ensure our asylum system is not creating pull factors that draw people on dangerous journeys across the world.

“Our approach remains in line with our international obligations and will encourage those who want to build a life in the UK to do so via safe and legal routes.”