Israel Adesanya says he was not the aggressor during a recent confrontation with a man in New Zealand … claiming the other guy started the whole incident by hurling a racial slur.

A source close to the UFC superstar tells TMZ Sports … as Izzy was parking his car on a roadway in his home country, the guy came out of nowhere and started calling him the N-word.

Soon after, our source says the man challenged Adesanya to a fight.

In video filmed by a witness — which has now gone viral on social media — it’s hard to make out what either dude is saying … although it’s clear both parties were pissed at one another.

Fortunately, the altercation never turned physical … and the two men eventually went their separate ways.

Adesanya is expected to address the incident at an anti-street violence charity later Thursday.