Ballam (20) won the men's 19 800m title in Christchurch last year and is hot favourite to take back-to-back wins in Dunedin.
The College of Education student was all class as he won the 600m sprint in a personal best 1min 19.90sec.
He is coached by Invercargill's Lance Smith.
"My coach told me to run it like a 400m and carry on," Ballam said.
He is a member of the Athletics New Zealand high performance squad that is preparing for the 2016 Olympics and ran a personal best 800m in 1min 50.15sec at the transtasman meet in Brisbane last month.
He wants to crack the 1min 50sec barrier and is targeting a time of 1min 48.50sec to qualify for the World University Games in China this year.
He has the second-best 800m time in the country this year and Olympian Nick Willis is the only one ahead of him with a time of 1min 46.89sec that he ranin Italy in September.
Marshall Hall (Taieri), the defending champion, warmed up for the New Zealand championships by winning the men's discus with 50.49m.
Kieran Fowler (Taieri) won the shot put with 14.77m from clubmate Jerram Huston with 14.77m. Huston threw 14.60m.
Taieri College pupil Holly Robinson (16) won the AWD shot put with 8.78m. She broke two New Zealand AWD records at the Otago-Southland secondary school championships on Saturday.
Robinson extended her own record by 2m to win the senior girls discus with 32.49m. She improved the shot put record by 11cm when finishing second in the senior girls event with 9.07m.
