This measure aims to raise an estimated £2 billion to help address a £40 billion deficit in the nation's finances.
The proposal involves levying an 8 per cent National Insurance contribution on rental earnings, which are currently largely exempt.
Supporters argue this would make the tax system fairer and could encourage landlords to sell, potentially increasing housing stock for buyers.
Critics, however, warn that such a move could lead landlords to exit the market, thereby restricting the supply of rental properties and driving up rents.