Police were notified of the incident at Illuzion on Bangla Rd at about 6am, following reports of a brawl inside the venue. The altercation is believed to have occurred at about 5:45am.
Bangla patrol officers brought all five women involved to Patong Police Station at about 6:20am for questioning.
According to the initial police report, the incident involved two British nationals, aged 25 and 24, and three Thai women aged 23, 25 and 28.
One of the British women suffered an injury to her forehead, while the second was uninjured.
Among the Thai women, one sustained bruising to her body, another suffered an injury to her mouth and the third received red bruising to her neck, police said.
No property damage was reported.
Patong Police said preliminary questioning found that both groups had engaged in a physical altercation and all injured parties were instructed to seek treatment at Patong Hospital before further questioning.
Investigators have filed an official police report and are reviewing CCTV footage from inside the venue to establish exactly how the incident unfolded.
Police said officers will continue interviewing those involved as part of the investigation. No charges had been announced at the time of reporting.