A group of apartment owners in Sydney's north has had to find millions of dollars to rectify defects in their complex which emerged since it was completed 10 years ago.

The developer behind the project — 82-84 Belmore Street Pty Ltd — was liquidated two years after the apartments were built.

The four buildings between Belmore and Porter Streets in Ryde, known as the Bayview Apartments, contain about 350 units and were completed in 2010.

It is the latest apartment complex in Greater Sydney revealed to have left owners out of pocket due to defects within the first few years of settlement.

The owners estimate it has cost them several million dollars to rectify the defects over the past decade. 

Among the problems to emerge was a plastic hot water pipe system in buildings C and D that had to be replaced with a copper network in 2018, costing $2.8 million between about 150 unit owners.

Burst pipes in the buildings set unit-owners back more than $132,000 over four years before they were replaced.

Owners also spent more than $70,000 on repairs in the basement of Building D to fix drainage problems, more than $90,000 to repair render on the same building and $20,000 to rectify communication seals across several buildings because of a fire-spread risk.

Many of the issues were documented in a building defect report commissioned about five years after the buildings were completed.

While the report listed the defects it did not determine who was responsible for them.

Problems with the air-conditioning system was more recently documented in a series of reports provided to the owners corporations, showing it is set to cost owners thousands of dollars.

Strata chair Andrew Murray said many owners were frustrated.

"We are determined to make this building good," he said.

"For 20 years, NSW governments allowed builders to thrive through poor regulation.

"They are only just beginning to get their act together."

Mr Murray said the extra costs had put a big strain on residents when they were not expecting any further expenditure.

"The hot water and the air-conditioning costs were a tremendous shock," he said.

"Many of these people are ordinary young families with their mortgages and not much extra cash.

"I feel terribly sad for the young families and even retired pensioners who have bought in and have very little extra money to meet those sudden expenses."

Investigations by the owners corporations to pursue the developer for any alleged responsibility, found it was highly unlikely legal action could proceed because the company had been wound-up and the warranty period for the buildings had expired.

It was developed by 82-84 Belmore Street Pty Ltd, a subsidiary of Holdmark Group and formerly directed by prominent Sydney Developer Sarkis Nassif.

The company was liquidated in 2012, about two years after the buildings were completed.

Mr Nassif is the founder and director of Holdmark Holdings.

A recent investigation commissioned by the Bayview Apartment strata managers, found early attempts to ask parent company Holdmark for help with water-proofing issues in the basement in 2012 only resulted in the installation of drip-trays.

Under new laws which came into effect in July, developers are compelled to rectify serious defects on apartment buildings within 10 years.

A spokesperson for Holdmark said it was willing to work with the owners corporations but claimed it had received little feedback.

It also said the issues raised with it were outside the warranty period.

"Holdmark has a reputation built on quality and a strong history of working constructively with owners and tenants to resolve any issues," they said.

"The building in question was completed in 2010 and has been occupied for more than a decade.

"After completion we worked constructively with the owners corporation to undertake rectification works.

"Much of the work undertaken was outside of the relevant warranty period but we were more than happy to assist the owners corporation."

The spokesperson said at the end of the six-year warranty period, the owners corporation commissioned a building report detailing a range of building and "wear and tear maintenance issues of a lived-in apartment complex". 

"We engaged an independent consultant to review the report and to work with the owners corporation to assess and work through any issues," he said. 

"We attempted to arrange times to conduct joint inspections of the building and start this process but received no response." 

Holdmark declined to provide ABC News with a list of items it helped to rectify on behalf of 82-84 Belmore Street Pty Ltd.

The Holdmark Group has more recently completed a number of other residential projects in nearby Meadowbank.

NSW Shadow Minister for Better Regulation Courtney Houssos is one of seven parliamentarians conducting a review into the "Regulation of building standards and disputes".

She said more still needed to be done to protect apartment buyers across the state.

"You have more protection buying a $100 appliance than a $1 million dollar property in Sydney," she said.

"Buying an apartment in Sydney should bring joy and financial security, not heartbreak and financial ruin.

"The plight of the Bayview Apartment owners shows the system is broken and needs fixing urgently."