Zetland, Epping, Brisbane City, and Southbank are among the suburbs that pose the highest risk to off-the-plan apartment investors, according to property risk analysis company, Riskwise.

Riskwise decided to compile a list of the top-100 most risky suburbs for off-the-plan sales, as concerns about apartment oversupply began ringing alarm bells across the country.

"The widespread oversupply issue is universally acknowledged by banks, including the Reserve Bank of Australia," said a statement from the company.

Many banks have compiled ‘blacklists’ for postcodes suffering from apartment oversupply, said Riskwise.

Despite the concerns, the unit market continues to grow, with more than 315,000 units approved for construction across Australia over the next two years.

Riskwise says five factors increase the risk of an off-the-plan apartment investment.

1. Poor economic growth in the suburb.
2. A high proportions of new units.
3. Off-the-plan units are a weaker investments than new houses.
4. CBD units deliver weaker capital growth than units in the middle ring. 
5. The higher the renter ratio, the poorer the capital growth performance of off-the-plan dwellings. 

Riskwise used those five factors to compile a list of 'The top 100 oversupply danger zones', after analysing more than 3,000 suburbs.

The top 100 oversupply danger zones

Zetland, a former industrial zone 4km south of the Sydney CBD, held the top spot. Lying at the heart of the Green Square urban renewal project, since 2016, more than 5,000 new units have been built in the suburb and in neighbouring Waterloo.

Read more about 'black list' suburbs:

ANZ issues lending 'blacklist' for Perth and Brisbane

Citi clamps down on lending in 'blackspot' suburbs

APRA tightens bank rules to restrict risky lending