Private landlords would be banned from above-inflation rent rises over a three-year period if Labour wins power, Ed Miliband has announced.

The move is part of a promised package of measures to help the growing numbers unable to afford to buy their own home.

Mr Miliband said there were also plans to replace “insecure” one-year tenancies with standard three-year contracts.

The Green Party is also proposing an inflation-linked cap on rent rises.

Speaking ahead of the launch of the policy tomorrow, leader Natalie Bennett said: “Sadly, as it stands, the private rental market is structured in a way that benefits landlords over tenants, and treats homes as investment vehicles. As more people rent, rather than own their homes, it is vital that we correct this imbalance.”

Tories said the move would suppress house building and see rents artificially inflated in advance, and spike every three years.

Liberal Democrat spokesman Lord Paddick said: “The only way to keep rents under control and stop house prices from spiralling is to follow the Lib Dem plan of building 300,000 homes.”

Members of Brighton and Hove’s Living Rent Campaign presented a manifesto to Brighton and Hove City Council’s housing committee last year, demanding changes to the rental market.

It listed six points which called for private landlords having to apply for a property licence from the council, a living rent commission to monitor and control rents to make sure they are not too high and six month tenancies to be replaced by three to five-year tenancies to increase security.

The campaign also wants a landlord accreditation scheme, which would show residents which landlords are considered ethical, support for ethical letting agents across the city and support for the building of council homes which would be let at a living rent price. More than 30% of Brighton and Hove’s homes are privately rented and the campaign says rents should cost only a third of monthly income.

Generation Rent director Alex Hilton said Labour’s plans were “riddled with holes”.

He said: “In order to level the playing field, all landlords should pay a fairer share of tax – a levy of 22% on all rental income would recoup the £9 billion housing benefit that goes to landlords and could fund 100,000 social homes a year.”