Street, who is up for re-election in May, has no planning powers, but says he opposes any housing development on green belt land in the Black Country for at least 10 years.
His stance puts him at odds with the officers at the four Black Country councils who concluded before Christmas that a lack of sites for housing justified a review of green belt boundaries in the area.
The urban capacity review was published as part of a review of the Black Country Plan, which is being jointly prepared by Wolverhampton City, Dudley, Sandwell, and Walsall councils. All four authorities form part of the West MIdlands Combined Authority, which is chaired by Street.
However, speaking this week, Street said: "In the West Midlands, we are leading the way in reclaiming derelict brownfield areas to build new homes and the fact is we have plenty of such sites.
"For this reason, and having looked at population projections, I do not believe there should be any new green belt development in the Black Country between now and at least 2031."
In his so-called Green Belt Pledge, Street pledged to work with councils to provide viable alternative brownfield sites, and to bid for an additional £200m to clean up derelict and contaminated sites.
He also said he would block the use of any West Midlands Combined Authority money for development on the green belt.
In addition, he said he would create a team of specialists to help councils and developers increase densities on brownfield sites and in town centres.
The mayor further said he would call on the government to review the National Planning Policy Framework (NPPF) to give the green belt greater protection.
This would include giving local areas powers to challenge "objectively assessed need" figures based on Office for National Statistics population projections.
Another recommendation was that councils, following the adoption of their local plans, should be required to approve development on brownfield sites first, with "any proposals for green belt development blocked until they are the last possible option available".
In addition, he said he would call for a review on the presumption in favour of sustainable development enshrined in the NPPF.
Street said: "I would rather see new family homes built on cleaned-up brownfield sites in the Black Country, or new apartments built in Birmingham City Centre, than diggers tearing apart our green belt.
"My ‘Green Belt Pledge’ lets the people of the West Midlands know that the Mayor will be on their side when it comes to fighting unwanted proposals from developers."
Street was first elected in 2017 pledging to "build the houses we need and protect the green belt", as well as prioritising brownfield sites for development.
In addition to the four Black Country authorities, the West MIdlands Combined Authority's constituent councils also include Birmingham, Solihull and Coventry.