As police went to arrest the men, the New Zealand diplomat allegedly pushed them and kicked the patrol car.
But after he was taken to Yongsan Police Station the man was freed after he invoked diplomatic immunity, the report stated. The Vienna Convention gives foreign diplomats immunity from civil or criminal prosecution.
Foreign Minister Murray McCully said this morning that on June 9 he signed a document that waived immunity for the diplomat, which allowed local police to interview the man.
"I think it is well established that we expect diplomats in New Zealand to behave well and be accountable under our laws, and we try and take the same approach in other people's jurisdictions."
Mr McCully would not go into the details of the allegations, but said reports in Korean media were "completely incorrect" to the best of his knowledge.
"They are certainly incorrect about the process, anyway."
He would not give details about the seniority of the diplomat, but said it was not New Zealand's ambassador.
The person was connected to the embassy.
"New Zealand officials from a number of agencies are covered by diplomatic immunity in places like Korea ... despite the report out of Korea that he had invoked immunity, that wasn't required. It applied to him until it was lifted by the New Zealand Government."
In a statement, Mfat said it took the matters seriously, and expects its representatives to abide by local laws.
"Korean police allege that an altercation took place outside the bar and wish to interview the government employee who was at the same event. The waiver of immunity allows the police to interview the government employee and press charges, if required.
"The ministry will not offer further comment while a police investigation is under way."
This year Malaysian diplomat Muhammad Rizalman bin Ismail was sentenced to nine months' home detention after he broke into the home of a Wellington woman without his pants and defecated outside her home.
The envoy left New Zealand in 2014 despite facing attempted rape charges after a botched email gave Malaysian officials the impression he was entitled to diplomatic protection and it would be acceptable for Mr Rizalman to return to Malaysia.
He was returned under extradition on October last year and pleaded guilty to indecent assault in November and sentenced in February this year.
More than 60 diplomatic staff or family members have sought immunity for offences committed in New Zealand in the past 20 years, including for 25 serious criminal matters of a sexual or violent nature.
New Zealand officials applied to have diplomatic immunity waived in 13 of these cases, which range from drink-driving to assault, and a waiver was granted on seven occasions.