Thomas Validakis, 30, was serving a suspended prison sentence when for drug matters when he is accused of letting off the explosive device inside the unit block on Virginia Street, North Wollongong last November.

Court documents said the ex-lovers were together for 18 months before their relationship came to an end in August 2018 and the woman moved on with another man.

She and her new boyfriend told police they were asleep inside their unit when they were woken by large explosion just before 2am on November 5. That bang was followed by a suction/vacuum sound then a second bang, they said.

The woman said she opened her front door to see the stairwell full of smoke and debris still settling, but she could smell firecrackers and there were cracks in her front door, a neighbour's front door and on the ceiling. A six-panel window pane was also completely shattered.

The woman told police she and Validakis had a sour history. Subsequent forensic examination of pieces of the firecracker were found to contain Validakis' DNA. 

Validakis was arrested earlier this month over the incident. He denied involvement when questioned, claiming he'd been at the unit complex "ages ago" and the explosion must have "stirred things up" which resulted in his DNA being located on the pieces of fuse.

Magistrate Mark Douglass agreed to grant Validakis strict bail after his lawyer said he would abide by any conditions imposed on him.

As part of his bail, Validakis is barred from entering Virginia Street, can't leave his house at night and must report to police daily.