A paedophile father caught with more than 780,000 child porn images and videos on hidden hard drives has been jailed for a second time.

Mohammad Salih's enormous stash of underage porn included hundreds of thousands of victims as young as five years old.

Some of the images and videos found at the 55-year-old's home in Australia fell into the most extreme category of child porn.

Salih was jailed for four-and-a-half years in the County Court of Victoria, Melbourne on Monday (20 November), the Australian Associated Press reported.

He must serve two-and-a-half years in prison before being eligible for parole.

The court heard how the father-of-one, who hasn't seen his son for nearly 10 years, was previously jailed for two years in 2008 for possessing and making child pornography.

He had been found in possession of about 400,000 illegal images and videos.

After release from prison, he came to the attention of the police again when he failed to notify the authorities he had created a new email address and set up online usernames, which violated his reporting obligations as a sex offender.

In May 2015, his home was raided by police and a laptop found to contain child porn was seized. A further raid uncovered two hard drives, including one hidden in a printer.

Salih was charged in February 2016 after what judge Claire Quin described as "a very large amount [of child porn], relating to hundreds of thousands of victims" was recovered from his computer equipment.

"This material was for your personal use, your activity does, however, provide a market for the exploitation of vulnerable children," Judge Quin she said during sentencing.

She added: "It's apparent that the sentence of imprisonment and time on parole didn't deter you from reoffending in a similar manner."