A man has told a Sydney jury he had absolutely nothing to do with a parcel bomb that maimed his friend in 1998 but fled Australia because he knew he would not get any police protection.

Roberto Saenz de Heredia denied he was scared of being convicted of attempted murder when he left the country in 1999 using a friend's passport after he was ordered to stand trial on the charge.

The 48-year-old also said he did not know how his DNA got on the parcel's stamp or his fingerprint on the card, but he had a "belief" how that happened.

He was giving evidence on Monday in his District Court trial, where he has pleaded not guilty to causing grievous bodily harm with intent to murder Brett Boyd in June 1998.

Mr Boyd, who died a decade later, lost a thumb and an eye, and suffered head injuries in the explosion at his Belrose home and told first responders the parcel had been addressed to his girlfriend Simone Cheung.

He also told police he owed $80,000 to de Heredia and another friend, Leroy Stolezenhein, who has also since died.

Defence barrister Paul Rosser QC on Monday asked de Heredia if he had anything to do with the bomb.

"Absolutely not," de Heredia replied.

After he was ordered to face a trial in August 1989, de Heredia was granted bail with conditions including he report daily to Randwick Police Station.

Mr Boyd was later arrested armed with a machine gun and pistol near the police station and de Heredia said this led to him leaving the country.

"I knew I was not going to get any protection from the police and I had to go," he said.

Nobody else was in court to hear the bail reporting condition except the police, he added.

De Heredia said he was hospitalised after trying to kill himself in September 1998 because Mr Boyd had made threats to harm de Heredia's brother.

"You attempted to take your own life because you were well aware of your involvement in the bomb," suggested prosecutor Virginia Lydiard.

"Not correct," he replied.

"My only way out in my mind was to remove me from the equation, I didn't think my brother would then have any problems or danger."

The trial is continuing.

AAP

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