THE discovery of thousands of unused burial plots and a rapid increase in cremations have added about 30 years to Sandgate Cemetery's lifespan.
It is estimated more than 5000 unused plots, many of which were bought for a pittance more than 50 years ago, are potentially available for use.
"Before we can do anything we have to try and contact the families who bought them originally," cemetery manager Chris Pryke said.
"Many have moved on so it will be a drawn-out process."
Previous modelling estimated the 16-hectare cemetery, one of the state's largest, would be full by 2034.
The recent acquisition of a significant parcel of land behind the service station on Maitland Road has helped relieve pressure on the cemetery, which opened in 1881.
The cemetery's new-found space has coincided with increasing numbers of people choosing to be cremated.
"About 80 per cent of people are now cremated," Mr Pryke said.
"We have unlimited space where ashes can be interred."
A garden area, suitable for burying or scattering ashes, will be part of an Italian crypts development. Work on the $250,000 project is due to start in March.
"We think it will be a very popular option for younger generations who will be cremated but want to be near their parents," Mr Pryke said.
There are also plans to consolidate several open spaces to create new burial plots.
"Sandgate is nothing like a typical Sydney cemetery where if you turn half a metre you run into a gravestone," Mr Pryke said.
"We have a massive amount of room on either side of the main corridors that run through the cemetery."
Mr Pryke said it was unlikely Sandgate Cemetery would be affected in the short term by recent legislation that allows for the resale of burial plots after 25 years.
"It's more of an issue in capital cities rather than here," he said.