His next parole hearing will be in August 2019.
In February 2007, McEwen and his co-offender Christopher Mana Manuel were both dressed in reflective vests to look like policemen when they knocked on the door of the tourists' campervan about 10pm.
McEwen then produced a shotgun and held it under the man's chin and demanded money.
The couple were handcuffed and gagged and the woman was raped inside the campervan while Manuel stood guard over the man outside. McEwen told the male tourist that if he did not give him the PIN to his bank account he would rape her again.
As the sentencing of the pair Justice Tony Randerson said McEwen - who he described as a career criminal with more than 100 previous convictions - carefully planned the attack and obtained everything he needed to subdue the couple, including a shotgun, duct tape, reflective vests and plastic ties to use as handcuffs. He tried to force the woman to take sedatives before he sexually violated her.
The violation was ''cruel and sadistic in the extreme''.
During the horror attack the pair took $3000 worth of property from the Dutch couple.
They had come to New Zealand on their honeymoon and hoped to become permanent residents.
"What should have been an exciting adventure touring New Zealand turned into a nightmare,'' Justice Randerson said.
"It's hard to imagine the horror you've perpetrated on this couple while they should have been enjoying their honeymoon. You've shattered their lives,'' Justice Randerson told McEwen.
Manuel, 27 at the time, was jailed for nine years with a non-parole period of six years after the judge said he accepted his remorse and he was not the main offender. He was released on parole in October 2014.