New Zealand is reportedly unlikely to demand the extradition of a South Korean diplomat who has been accused of sexual assault.

According to news website Stuff, despite months of strong lobbying by New Zealand foreign ministry officials for cooperation from their South Korean counterparts, the issue appears to have dropped off the diplomatic agenda.

Stuff reported Kim Hong-kon was issued an arrest warrant for allegedly sexually assaulting a male staffer at the Korean embassy in 2017. The warrant was delivered more than a year after the diplomat had left New Zealand. Kim has denied the charges. 

The outlet reports extradition of the diplomat - who is now in a third country - would not be possible without a guilty verdict from New Zealand's courts. 

New Zealand Prime Minister Jacinda Ardern, it said, pointed out a request for extradition would need to come from the police. 

Presidential Spokesman Kang Min-seok on Wednesday said the issue was raised during a conference call the day before between Ardern and President Moon Jae-in. He offered no additional details.