Ardern said the vaccine was "easier than getting the flu jab."
"I never wanted to be among the first but I also wanted to be a role model," she said.
"I'm choosing to be vaccinated at this point in order to play my role in demonstrating that I consider it to be absolutely safe, but also really critical to keep others safe," she added.
A plan for vaccine rollout for New Zealand's general population was announced on Thursday.
"Our vaccination program is ahead of plan, with nearly one million doses administered and operating at 107 percent of target," Ardern said, adding every eligible New Zealander will have the opportunity to be vaccinated by the end of the year.