"It was prolonged, it happened late at night, it happened with the victim's child present, there were opportunities to withdraw and you didn't," the judge said.
"She suffered physical effects and emotional effects and it's more than just assault; it's a cruel assault."
Bishop, whose parents, siblings, partner and daughter all live in Australia, was deported to Invercargill on November 4.
He is one of 140 deportees who have come before the court since arriving back in the country, police confirmed.
His return came only weeks before the Returning Offenders (Management and Information) Act was rushed through Parliament.
The legislation gave authorities the ability to impose parole-like conditions on deportees, as though they had served time in a Kiwi prison.
"The Australian policy is focused on returning offenders to New Zealand, not on any notion of reintegration and rehabilitation," the judge said.
"Conversely, the New Zealand Government swiftly provided an immediate response to support offenders in their return [and] act as protection for the community."
Bishop's lawyer, Louise Garthwaite, said he had not been in Invercargill since he was 9 and likened his return to being "dropped off in China".
His grandparents lived in the city but he moved to Dunedin soon after to pursue a relationship with the victim.
Though Bishop had no domestic violence on his Australian rap sheet, he had a history of violence, the judge said. "There are a number of convictions for assault. They appear to be serious."
But Judge Crosbie was impressed by a "lengthy and well-written letter" Bishop provided to the court, which he believed showed genuine remorse.
A letter from his grandmother was also highlighted.
"She says you need to learn not to rush into situations," the judge said. "That's pretty good insight from a nana."
Bishop is one of 513 Kiwis sentenced to a year or more in Australian jails who automatically lost the right to live there. The numbers:
• 513 Kiwis deported from Australia since new legislation enacted in December 2014
• 140 have been before the court since their return (27 per cent)
• 430 crimes have been committed
(as of August 31, 2016)