This comes after housing secretary Michael Gove launched a consultation proposing new legal requirements for social landlords to address hazards, including damp and mould.
On the topic, Rayner said: “We have 1.6m children living in mouldy, damp or cold houses that are in the private sector as well.
“You can't distinguish between social landlords and private landlords — mould is mould.”
Rayner also posted on X: “There is no justification for letting private landlords off the hook for resolving mould and damp issues in their properties.
“The Tories are refusing to extend protections to private renters.
“A Labour government will.”