An Australian man has been sentenced to 129 years in a Philippine jail as part of a child sexual abuse case involving victims as young as 18 months, a prosecutor said Wednesday.

"I hope this sends a very strong message to all abusers, all human traffickers, that crime really does not pay," Merlynn Barola-Uy, a regional prosecutor in the southern city of Cagayan de Oro, told AFP.

It was the second conviction for Peter Gerard Scully, who is already serving a life sentence for rape and trafficking of girls.

The Philippines has become a global hotspot for child sex exploitation, experts warn, helped by poverty, English fluency and high internet connectivity in the country.

The Cagayan de Oro court handed down the sentence on November 3 after Scully and his three co-accused entered into a plea bargaining agreement.

They had been charged with 60 offences, including trafficking, child pornography, child abuse and rape.

Scully's girlfriend, Lovely Margallo, was sentenced to 126 years in jail. Two others were given sentences of more than nine years.