"He was brought from the water and given medical attention but unfortunately was not able to be revived," a police spokesperson said.
The South Coast Boardriders Association's Facebook page stated the surfing event was "held in remembrance of past club members Robert Herbert and Matthias Paro".
About 50 people had gathered at the beach to watch the competition.
A witness at the scene said he was watching surfers at the beach when a helicopter arrived with a paramedic to tend to an injured surfer.
He said he had rarely seen waves so large at the beach.
It was "definitely a big day", but the conditions did not seem dangerous to him and all of the surfers he saw seemed experienced.
On Facebook, the South Coast Boardriders Association posted a remembrance and an opportunity to support Civil's mourning family through the crowdfunding site givealittle.co.nz.
"The New Zealand surfing community lost one of its most respected surfers . . . when Jamie Civil drowned while surfing huge waves," the statement read.
The association stated Civil's partner Courtney and daughter Lenni were at the beach when the drowning happened.
"He loved them both dearly.
"They had become a perfect part of his world, and he loved the beautiful life they had created," the statement read.
The money raised through givealittle.co.nz would help Civil's partner and daughter "adjust to the sudden shock of life without their partner and Dad".
Two pages on the crowdfunding site have so far raised more than $25,000.
Te Runanga o Otakou placed a rahui (temporary closure) on the area from Heyward point to the Spit until 3pm Sunday.
Food gathering and swimming are discouraged until the rahui is lifted.
The death will be referred to the coroner.
