A one-bedroom apartment in Auckland's CBD has been marketed as being suitable for up to four tenants.

The unit's property manager says the apartment is appropriate accommodation for three or four international students.

But the Migrant Workers' Association of Aotearoa compared such cramped living conditions to those of slaves.

SUPPLIED The bedroom of an Auckland central apartment said to be suitable for "up to four tenants" has two beds about a metre and a half apart.

The organisation, which advocates for the rights of international students, believes housing several people at such a small property was unethical and is calling for the practice to be banned.

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The median weekly rent for a one-bedroom apartment in Auckland Central East during the last six months was $400, according to the Tenancy Services' website.

The unit, at 4 Lorne St, is advertised online for $500 per week.

It is modern and fully furnished. The bedroom is spacious but doesn't have a door separating it from the rest of the apartment - instead you enter the room through a narrow hallway.

Inside are two beds, a king and a single, about two metres apart.

SUPPLIED The lounge, minus the sofa bed, of a central Auckland apartment marketed as suitable for "up to four people".

In the lounge is a sofa bed. This is where a fourth person could sleep, said the property manager, who identified himself only as Su.

The apartment has one bathroom, which is accessed through the lounge.

By Tuesday afternoon, a day after Su listed ads on New Zealand, Chinese and Korean websites, he said at least 10 people had contacted him about viewing the apartment. Most were international students who wanted to share the flat with other people.

The Housing Improvement Regulations 1947, which are managed by territorial authorities, govern accommodation overcrowding. They state three people can only share a room if it is 14sqm or larger.

Su said he was aware of the rule. Although he did not know the exact area of the Lorne St apartment's bedroom he was "pretty sure" it was bigger than 14sqm and told Stuff he would double check the dimensions with the apartment's owner.

He believed the apartment was suitable for three to four international students because it had three beds.

SUPPLIED The bathroom of a central Auckland apartment, which is being marketed as suitable for up to four tenants.

"They will be fine with that. The owner doesn't mind about it."

Migrant Workers' Association of Aotearoa spokesman Sunny Sehgal said many international students were living in overcrowded properties.

He had heard other cases of "greedy landlords" cramming more than 20 people into a two bedroom apartment.

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"Our concern about this is that the living conditions are absolutely hostile," Sehgal told Stuff.

"Charging four or five people $90 each and everyone living in one room, even if it's legal it's not ethical."

He said landlords who allowed international students to live in overcrowded accommodation should be penalised and a law change was needed to prevent overcrowding.

SUPPLIED The lounge of a central Auckland apartment that is being marketed as suitable for up to four people.

"Someone has to step up and put a full stop on this kind of behaviour."

Tell your renting story by contacting Stuff at brittany.keogh@stuff.co.nz

Mervyn Chetty, Auckland Council's manager of environmental health, said breaching Housing Improvement Regulations was an offence. If convicted homeowners could be fined up to $40. Those who continued to flout the rule could also be fined $10 per day, or part day.

In March, Auckland Council shut down a Japanese-style "sleeper pod" apartment in the CBD after it was found to have breached several bylaws.

The sleeper pod accommodation first made headlines in September last year when individual pods were listed for rent on Trade Me for up to $200 per week.

Karen Withers, president of the Independent Property Managers' Association (IPMA), said most property managers tried to ensure the number of people living at a rental properties did not exceed recommended numbers.

"We're usually in trouble for policing it the other way interestingly."

The Healthy Homes Guarantee Act 2017, which comes into effect next year, would set standards for rental accommodation.

"We are keen to see a licensing system for all landlords," said Withers.

Su said he was not a member of IPMA.

How to seek help if you think you are living in inappropriate rental accommodation