He abused four children under the age of 16 in the Philippines in 2017 and kept recordings on his phone.

He also encouraged others to abuse kids overseas, said he would buy a boy from the slums and on occasions offered $150 for child exploitation material.

In messages, he expressed a desire to "tie young children up and tape their mouths".

In recently published sentencing remarks, Supreme Court of Tasmania Justice Tamara Jago said Nettleton had a distorted sense of morality.

After being bailed following his March 2018 arrest, Nettleton posted on Facebook saying the Australian Federal Police were focusing on a technicality and making it a massive deal.

"Such communications obviously disclose a most concerning absence of insight and understanding of the harm his actions inevitably caused," Justice Jago said.

"(He) sought to minimise the seriousness of his conduct and displayed no remorse."

Nettleton initially told police he hadn't committed a "mortal sin" and someone had told him the legal age of consent in the Philippines was 12.

He pleaded guilty to charges including engaging in sexual intercourse with a child under 16 years of age outside Australia and producing and transmitting exploitation material.

Nettleton was sentenced to 12 years' jail with a non-parole period of six years, backdated to November 2019 when he was taken into custody.

Justice Jago said the children in the Philippines were particularly vulnerable, partly because of their economic circumstances.

She said Nettleton's conduct was of the "upmost depravity" and warranted a lengthy jail term.

Such behaviour was "rightly regarded as abhorrent", she said.

Nettleton will be placed on the sex offenders register for 25 years once he is released.

1800 RESPECT (1800 737 732)

National Sexual Abuse and Redress Support Service 1800 211 028