Hirini, captain of the reigning Sevens world champions and the Olympic champions, told rwcsevens.com, "I'm excited as it is my first time here in Cape Town, and for a Rugby World Cup too, it is a pretty cool place to play.
"I know there are a lot of Kiwi supporters in Cape Town, so we're looking forward to the fans coming out and cheering us on."
New Zealand plays Colombia in their opening game.
"Competing in Rugby World Cup Sevens means a lot. Watching it, you see how this tournament is the pinnacle for so many rugby players.
"I'm really looking forward to how special this is going to be this weekend."
However, she was mindful of the knockout nature of the competition and the need for the Black Ferns to be consistently on their game.
"With the knockout competition, it can be hard to look beyond the next game, but we hope we'll do well.
"When you come to a pinnacle event you want to go all the way. We've done that a few times and it was pretty special for New Zealand," she said.
Gunning for the title will be New Zealand's trans-Tasman rivals Australia, the HSBC World Series and Commonwealth Games winners.
Captain Demi Hayes said her top-ranked side wanted to back up the form they showed to claim those titles.
"We've spoken about consistency the entire season, and this would top off our whole season. Our group has trained so hard since the Commonwealth Games and we're excited to get going."