Police were called to a house on Whitcombe Street in the South Canterbury town just after 10 o'clock last night after two men had been stabbed.
The two victims were taken to hospital and one man, who remains in a critical condition, was transported to Christchurch Hospital overnight.
The second person suffered minor injuries
Police said a 25-year-old man will appear in Timaru District Court tomorrow.
They are not looking for anyone else in connection with the stabbing.