The veteran administrators have been involved with several other large golf tournaments, such as the past seven New Zealand PGA tournaments at Clearwater, near Christchurch.
This is Mrs Harrington's first involvement at The Hills.
Her main job was to ensure things ran smoothly and the appropriate volunteers were in the right place at the right time.
As with the first NZ Open played at The Hills in 2007, more people volunteered than were required.
The volunteers fill roles such as roving marshalls, scorers, radio communications, results board attendants and drivers.
People from all around the country had volunteered, with successful applicants travelling from Auckland, Christchurch, and Dunedin, Mrs Harrington said.
The 400 included many people from various Central Otago and Southland golf clubs, who were assigned holes around the course to marshall, she said.
One of the attractions for many of the volunteers was the opportunity to play Michael Hill's private golf course.
A tournament for the volunteers will take place tomorrow, with a second date set down for May 2.
