A contractor who dumped eight truckloads of hazardous waste containing asbestos on residential land could be paying off fines for similar offences beyond 2072, a Sydney court has heard.

Dib Hanna, 38, has dozens of criminal convictions and more than 20 fines for illegally dumping building material across Sydney.

In 2013, he was given a three-month suspended jail sentence and good behaviour bond for contempt of a court order to stop illegally dumping hazardous material.

The waste removal contractor is paying off hundreds of thousands of dollars in fines at a rate of $300 a month through the New South Wales Debt Recovery Office.

It is estimated the fines will not be paid off until 2072, when Hanna is aged in his 90s.

Hanna on Wednesday faced the NSW Land and Environment Court to be sentenced for dumping 80 tonnes, or eight truckloads, of building material containing asbestos on a residential land site at Picnic Point over the 2012 Easter holidays.

He broke into the site and dumped waste that included metal, glass and material containing asbestos.

The dumping was caught on CCTV cameras and Hanna later pleaded guilty to four charges.

He told the court he could not recall where the material he dumped at Picnic Point came from.

He said someone showed him where to put it but he could not remember who.

Hanna said he was only paid a few hundred dollars for each load of building waste he transported and tip fees absorbed most of that money.

The contractor said he was "sorry" and that he had health issues related to a stroke last year.

Hanna has 'Damascus-like conversion' in witness box

Prosecutor Michael Wright said Hanna's actions were brazen and deliberate, and the consequences for the land owners - a couple who planned to build on the land - were serious.

He called for a strong deterrent, given Hanna's prior convictions for dumping and the public health risks of dumping asbestos.

"These offences were deliberate and opportunistic in nature," he said.

"He has a very long history of offending."

Mr Wright added: "He will be paying fines until 2072."

He noted that under current legislation in NSW, a jail sentence was not available for Hanna's Picnic Point dumping offences but he could be fined up to $250,000.

Defence lawyer Stephen Stanton said Hanna had experienced a "Damascus-like conversion" in the witness box and was remorseful for his crimes.

He called on the judge to "show mercy" and mentioned his client's serious health problems.

But Justice Brian Preston questioned if Hanna's remorse is genuine, noting that he kept reoffending.

The judge reserved his decision to a later date.

Hanna made no comment outside court.