Hotel pool cleaner's suspected motive for allegedly killing Aussie couple and their relative at Tagaytay Lake Hotel in the Philippines

A former pool cleaner who allegedly murdered two Australian tourists and their relative in their hotel room in the Philippines may have been motivated to seek revenge on his ex-employer and to fuel an online gambling addiction, a court has heard.

Ronel Estipona Perido faced a closed court on Thursday after he pleaded not guilty to murdering Sydney man David Fisk, his 55-year-old Filipino-Australian partner Lucita Cortez, and her Filipino daughter-in-law Mary Jane Cortez, 30, in July.

It's alleged Perido entered the family's room at the popular Tagaytay Lake Hotel, 70km southwest of Manila, through a balcony window while the trio were asleep.

Police are investigating whether he allegedly murdered Mr Fisk, 57 and then ordered the women to transfer money to his online account before allegedly killing them.

The dead trio were found lying face down with their hands and feet bound with electrical cord and tape over their mouths.

Perido, believed to be aged in his 20s, was allegedly fired from hotel for stealing and may have sought revenge after failing to receive his final pay cheque, the Sydney Morning Herald reported.

He was arrested days after the Tagaytay mayor told the local police chief they would be fired if they failed to make progress on the case within a week.

While the Philippines defaultly closes courtrooms to the public and media, Australian reporters got a chance to question Perido, who wore a bright yellow shirt with the words 'Person Deprived of Liberty', outside court.

When asked if he had anything to say to the families of his alleged victims, Perido shook his head.

The accused killer sat on a wooden bench outside the courtroom with his aunt, who was there to offer her support.

Just metres from the pair stood Rico Cortez, Lucita's son and Mary Jane's husband.

'When I saw him, I was mad. I wanted to approach the guy,' Mr Cortez told the publication.

He was forced to quit his job as a delivery driver following his wife's death to focus on raising his four children. The youngest is just four.

He's grateful for the help of his eldest daughter, 12, whom Mary Jane taught how to cook and clean.

'She would always tell them, 'What if I am not here anymore?',' Mr Cortez said.

Mr Fisk's family were unable to attend the court hearing in Tagaytay but have hired a private prosecutor, Friedrick Vincent C Lu, for their criminal and civil claims.

As well as action against Perido, the family will sue the Lake Hotel for allowing the allegedly disgruntled employee access to its premises.

Mr Lu read a statement on the family's behalf, in which they said they were 'blindsided' by the 'senseless' alleged attack.

'David was someone's father, brother and son whose life was senselessly taken in such a violent manner in a country far from their own,' he read

'This has left them with so many questions unanswered and, more than anything else, they seek justice to its fullest extent.

'The swift action of the local government authorities of Tagaytay City has not gone unnoticed and the family wishes to extend their gratitude.

'Their prompt action provided a measure of solace to David's family during this difficult time, and they remain hopeful that these efforts will lead to the prosecution of those responsible.'

It's understood Perido is seeking advice for a plea deal.