If you needed a sign Brisbane has an apartment oversupply, a two-bedroom unit with city views in one of the most trendy suburbs has just gone for $50,000 less than it was bought for two years ago.

Top five reasons for apartment price plunge: Oversupply

Oversupply Crackdown on foreign lending

Crackdown on foreign lending Banks requiring higher deposits from domestic buyers

Banks requiring higher deposits from domestic buyers APRA cap on interest-only loans

APRA cap on interest-only loans Tougher lending criteria for developers Supplied: Property economist Peter Wargent - Wargent Advisory 2018

The Paddington unit, which sold for $440,000 after it was renovated, is just one of hundreds of units that have crashed in value since an apartment construction boom created an oversupply, with no end in sight.

It is not just small units affected, either. A big three-bedroom pad in South Brisbane is now on the market for $799,000, which is what it was sold for brand new 10 years ago.

A luxury three-bedroom unit at Toowong that would have snared up to $950,000 at sale two years ago has lost about $100,000 in value because of the soft market, according to its seller.

There are also plenty of investment units in middle-ring suburbs like Lutwyche, Mount Gravatt, Albion or Kelvin Grove.

Units in Kelvin Grove's Urban Village that were valued at $450,000 two years ago are now going for $399,000.

Agents in those areas are "submitting all offers" and taking buyers' low bids very seriously.

Unit prices down 4.5 per cent in 12 months

The latest Domain House and Apartment Price Report found Brisbane units prices were now at a four-year low, with a decline of 2.2 per cent over the December quarter to $385,955.

Domain data scientist Nicola Powell said that was a 4.5 per cent drop compared to last year.

"The surge of new apartments in Brisbane remains ahead of the demand," Dr Powell said.

"Although this continues to impact unit prices, population increases and a slowdown of new developments and completions may work together to help balance the market."

14-year-old apartment block at Toowong in inner-city Brisbane. ( Supplied: Position Property )

Owners accepting 'cheeky' offers from buyers

Space Property agent Nicole Devine had to break the bad news to her Paddington vendors about their city-view unit.

"Sellers really have to be honest with themselves and take feedback," she said.

"They can still can have a dream price, but have to be realistic and listen to market as well."

National Property Research Company director Matthew Gross said buyers had done their sums in this oversupplied market, and they were being cheeky.

"I think buyers have always been cheeky but now they are allowed to be cheeky," he said.

"They are going in and offering that 5 per cent to 10 per cent under the price, particularly for the established market, and they are getting results.

"It certainly is a buyer's market, but not everyone has to sell.

"What you are doing is playing a numbers game. But at the end of the day if you like the property, make an offer."

Rental income falling, less foreign investors

Property economist Peter Wargent said there were plenty of examples of falling rents, especially in the inner-city areas. There was also quite a bit of risk in the new or off-the-plan apartment sector.

"Lending to developers for new projects has been severely tightened," Mr Wargent said.

"We are seeing almost no lending now to offshore buyers, except to New Zealanders."

Mr Wargent said there were also higher deposit requirements for many investors to buy in inner-city at about 20 per cent to 30 per cent.

"The regulatory crackdown by APRA, which is now limiting the flow of new interest-only loans to investors in particular, is also discouraging investors, as is falling rents," he said.

Mr Wargent said the Queensland Government's move to hit foreign investors with a new property tax had also significantly impacted the market.

"It sent out a strong message that was not necessarily well received, so I'd say the Brisbane apartment market will remain pretty flat this year," he said.

Lounge room and view of three-bedroom apartment at South Brisbane. ( Supplied: Position Property )

GFC and floods impact price: agent

Position Property's Bradley Munro is confident his three-bedroom South Brisbane unit will sell to an owner-occupier couple who are downsizing.

Mr Munro blames the stagnant 10-year old price on the fact "we have had the GFC and the floods" during that time.

"Now we are going through a slightly different market in Brisbane so it is not surprising, given the last 10 years," he said.

"Without those things it would be a different story."

View from ground of units at Kelvin Grove in inner-city Brisbane. ( ABC News: Lexy-Hamilton-Smith )

Developer incentives, saving up to $50,000

Although the number of new inner-city projects coming online have slowed to a crawl, developer incentives were still on offer.

Mr Gross said first homeowner grants of $20,000 were being matched by some developers to help keep the prices for new apartments up.

One project at Enoggera is pitching its sales at '"re-construction prices — save up to $50,000", but that is not unusual either.

Coronis Agent Gerard Hawes said the investor market dried up in 2017 due to the crackdown on foreign investors.

"For those people looking for decent market value, our foreign investors did tend to push the values up on that property," Mr Hawes said.

"So we have seen a bit of kickback of around 10 per cent across the board."

There are always exceptions in a downturn, particularly at the top end of the market.

Boutique blocks like the London Residences at West End are selling to cashed-up buyers who have sold up in the suburbs.

As a sweetener, the 26 owners also go into a draw for a luxury car worth more than $90,000.