He says he wanted it for only two nights, so then he handed the keys to friends and returned home the day before the bust - and maintains there were no drugs in the villa when he left it.
He believes Ormsby - whom he met only once - is innocent.
Mr Byrne told Sydney's Daily Telegraph: "As far as I know, no one I spent time with on the trip had drugs or would be involved in something like this."
The discovery of drugs and Ormsby's arrest came as an "absolute surprise".
Denpasar police chief Djoko Hariutomo said Interpol had been asked for assistance, as police wanted to question Mr Byrne.
"We are also co-ordinating with Interpol regarding the last renter of villa," he told reporters yesterday.
"Whether there's a connection or not, we don't know yet. There's still no other suspect." Ormsby denied she owned the drugs, he said.
Ormsby told the Telegraph she doesn't want her family to visit her in jail until she goes to court, but she was holding up "okay" despite the grim conditions.
She was sleeping on a mat on the floor and locked in the same cell with several other women. Her lawyer was bringing her supplies which was helping her get through the notorious Bali jail system.
Ormsby can be held at the Denpasar City police station for as long as 30 days pending an investigation before the case is handed to prosecutors who will decide exactly what charges she will face.
Police have yet to announce which charges they will recommend to prosecutors but they reportedly are considering charges of dealing and possessing drugs.
Those crimes carry a maximum 20-year jail sentence.
Ormsby is from Rotorua, but had been living in Paddington, Sydney.
Her case follows that of Schapelle Corby who was released from a lengthy jail term only two days before Ormsby's arrest.
Kiwi behind bars
* Leeza Ormsby was arrested on February 12 at a villa in Bali where police allege they found 132.2g of MDMA and 26.06g of hashish.
* She denies the seized drugs were hers.
* Police are reportedly considering charges of dealing and possessing drugs, which carry a maximum jail sentence of 20 years.
- AAP