The Wanaka Night 'n Day Store was under a police cordon all day on Saturday as police investigated a serious assault.

A father-of-two brutally assaulted in Wanaka was about to celebrate a 10-year anniversary with his partner.

Instead of celebrating with his long term partner, Kahu Vincent remains in critical condition in Dunedin Hospital after he was allegedly assaulted in the Ardmore St Night 'n Day at 3am on Saturday.

The two men accused of the early-morning assault in the Central Otago town were remanded back into custody without pleas when they appeared before Judge Michael Turner in Queenstown District Court on Tuesday morning.

The gallery was almost standing-room only when a 40-strong contingent of Vincent's family, friends and supporters arrived for the 11am hearing.

A carpenter, 39, and a kitchen hand, 34, are jointly charged with causing grievous bodily harm with intent on Saturday.

The 39-year-old is also charged with attempting to pervert the course of justice by telling a third party not to talk to police or "I will find you and kill you."

Vincent's partner Jade Makuru, on Facebook, described him as the love of her life.

"To my gorgeous most amazing man, daddy to our beautiful kids and love of my life. As I write this tears stream down my face. I love you so so much and it hurts my heart so bad to see you like this.

"[Sunday] marks our 10-year anniversary and 10 of the most amazing and happy times of my life with you and I'm positive we will have many more.

"This isn't fair but I am sure you will pull through this and I'll get to wrap my arms around you again soon."

Judge Turner granted continuing name suppression and remanded the pair to Invercargill District Court for a bail hearing on Monday.

Police in Wanaka are still calling for any witnesses or information after the incident inside the Night 'n Day store shortly after 3am on Saturday.

Detective Senior Sergeant Colin Blackie said several people were inside the store and police would like those customers to come forward.

Police also want to talk to anyone who witnessed two men wearing crash helmets around the time of the alleged assault.