Angela Rayner is backing plans put forward by Sir Sadiq Khan to pedestrianise Oxford Street "as quickly as possible".
The mayor of London has previously tried to ban traffic from the famous shopping street but was thwarted by the then-Conservative majority Westminster City Council in 2018.
Sir Sadiq's office say 66% of people asked as part of a consultation on the plans backed the pedestrianisation.
Separate research from YouGov run in September last year suggested that 63% of Londoners support the project.
Ms Rayner, the secretary of state for housing, communities and local government, said: "We want to see Oxford Street become the thriving place to be for tourists and Londoners alike, and that's why we welcome the Mayor of London's bold proposals to achieve that.
"We will support the mayor in delivering this ambitious vision, which will help to breathe new life into Oxford Street - driving investment, creating new jobs for local people and providing a boost to economic growth in the capital."
This time around, the plans just need the backing of Ms Rayner, and the mayor is looking to create a mayoral development corporation by 1 January 2026 at the latest.
Sir Sadiq wants to restrict traffic from the 0.7 mile area between Oxford Circus and Marble Arch, with the potential for further changes towards Tottenham Court Road.
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The mayor's office claim that, of more than 6,500 responses to their consultation launched in February, "Londoners and businesses overwhelmingly back the mayor's ideas".
The proposal has the support of Ikea, Selfridges, John Lewis and the London Chamber of Commerce.
Detailed traffic proposals will be established later this year.
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Sir Sadiq said: "Oxford Street has suffered over many years, so urgent action is needed to give our nation's high street a new lease of life.
"It's clear that the vast majority of Londoners and major businesses back our exciting plans, so I'm pleased to confirm that we will now be moving ahead as quickly as possible.
"We want to rejuvenate Oxford Street; establish it as a global leader for shopping, leisure and outdoor events with a world-class, accessible, pedestrianised avenue.
"This will help to attract more international visitors and act as a magnet for new investment and job creation, driving growth and economic prosperity for decades to come."
(c) Sky News 2025: Angela Rayner backing Sir Sadiq Khan's plans to pedestrianise London's Oxford Street
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