The fight that broke out outside Pakatan Harapan's operations centre in Rantau last night was due to a payment dispute, according to police.

Negeri Sembilan acting police chief Mohamad Mat Yusop said a 50-year-old man, who tried to mediate in the dispute, was injured in the incident, the New Straits Times reported.

The fight broke out shortly after news circulated that Harapan's Dr S Streram was defeated in the Rantau by-election.

Among the conversation heard during the fight were blame being hurled at one another over Harapan's loss.

Streram was trounced by BN's Mohamad Hasan, who won with a 4,510-vote majority.