Rogue landlords are the target of new measures being considered by both the government and Labour.
The government says landlords in England who want to rent a property to five or more people, from at least two different families, should be licensed.
Under the plan, the maximum number of people who can occupy a room would be specified in the property's licence.
Meanwhile, Labour leader Jeremy Corbyn says his party wants tenants to have more powers to avoid eviction.
There are about 4.3 million households in the private rented sector in England. About 500,000 are houses in multiple occupation.
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The Department for Communities and Local Government said the changes, subject to Parliamentary approval, would make flats and one and two-storey properties subject to licensing.
National mandatory licensing currently only applies if properties are three or more storeys.
It estimated that about 160,000 homes will be affected by the new proposals.
'Rogue landlord crackdown'
The government has also brought forward minimum bedroom sizes in a bid to deal with overcrowding and poor accommodation.
It is already waiting for approval from Parliament for regulations, which outline offences including burglary, blackmail, stalking, fraud and fire safety offences that will lead to a landlord being banned from letting out property.
Those who are banned will be listed on a database from April.
Housing minister Alok Sharma said he was seeking to target "unscrupulous" landlords who profit from offering "overcrowded, squalid and sometimes dangerous homes".
He said: "Through a raft of new powers we are giving councils the further tools they need to crack down on these rogue landlords and kick them out of the business for good."
Elsewhere, Mr Corbyn told the Independent that he would abolish so-called "no fault" evictions in which people are asked to leave without reason.
"I think it's a moral litmus test for the country: do we just put up with so many rough sleepers or do we do something about it," he said.
Under Labour there would be an emphasis on longer tenancies are part of a "more regulated" private rented system, he said.
"I am very determined to bring some order and stability to their lives by longer tenancies and eviction that can only be there for good reason rather than just what can be retaliatory eviction," he said.