A man remains in serious condition in Christchurch Hospital following an altercation outside the Crown Hotel in Temuka on Saturday night.
Police were called to the hotel at 8.50pm after receiving a report of fighting outside the premises.
Detective Senior Sergeant Marion Neill said investigators are still working to establish how the injured man, whose name has not been released, became involved in the incident.
Another man and a woman were treated at the scene by ambulance staff.
The incident may have been related to a dispute between two groups of people that began earlier in the evening at the premises.
"We know there has been some sort of contact between these two groups, however it is unclear at this stage how the injured man became involved in this matter," Ms Neill said.
"We are speaking to witnesses and patrons of the premises, and also reviewing CCTV footage to put together a picture of the events that have taken place."
Crown Hotel owner Tim Curd declined to comment.
In the earlier incident, a 32-year old man was arrested for an assault on a 33-year old man. He will appear in Timaru District Court tomorrow.
Earlier Mid-South Canterbury area commander Inspector Dave Gaskin said Timaru police had spoken to witnesses to establish what happened and how the hospitalised man sustained his injuries.
"We've been speaking to people today [Sunday], but if anybody saw anything or think they know something we should hear about, we would love to hear from them. They just need to contact the Timaru police station," Mr Gaskin said.
People commenting on Timaru Herald social media sites had suggested someone had died following an assault in the township on Saturday night.
However, Mr Gaskin said this was not true.
He said last night no-one had died, but police were dealing with a serious assault.
The Herald has also been told that there were other violent altercations outside two Timaru taverns over the weekend, but police were unable to provide any information on these yesterday.
Anyone who witnessed the events or has information relating to what occurred should contact Timaru police on (03) 687 9808.
- The Timaru Herald