Tanya Carlson, Juliette Hogan and Harman Grubisa are also Kiwi staples hanging in the Prime Minister's wardrobe.
Ardern is a regular customer at the Ponsonby Road store owned by Tanya Carlson and the designer said Ardern usually shops alone and chooses her own clothes.
"She's is very comfortable with what she wears. She's young and she has quite a youthful edge to what she chooses," Carlson said.
"She is very aware of the effort that goes into designing and manufacturing in New Zealand and she has always been supportive of local industry."
New Zealand designers Emilie Pullar and Abby van Schreven from label Maaike custom made Ardern's election night outfit and were thrilled to see it the one-off burgundy shirt-dress and draped jacket splashed across front pages worldwide.
"We have had a relationship with Jacinda for a long time now and asked if we could custom make something for her for election night," Pullar said.
"We had a vision for what we wanted to make for her and she put her trust in us."
All of Pullar and van Schreven's garments are designed and made in Auckland - from fabrics bought at local markets to local pattern-makers and dressmakers. It's something they believe sits well with Ardern.
Fellow designer Ingrid Starnes was also thrilled to see her designs worn by Ardern at the televised Leader's Debate.
"It's been such an honour to be along the journey in a small way as Jacinda has chosen to wear our clothes for some of her big moments," Starnes said.
"Any time a woman chooses to wear things we've made for an important day it's a real thrill. But to see someone making history and in the New York Times in something that you were constructing that afternoon is a really special feeling".
PM Jacinda Ardern is set to put New Zealand fashion labels even further on the fashion map. Photos / Mark Mitchell, Brett Phibbs
Ingrid Starnes managing director Simon Pound said Ardern had long been a long-term supporter of the label, and local business.
"When she was Small Business Spokesperson she came to talk to us about local production, retail, and being an employer," Pound said.
"She really cares about all sides of the work equation, and walks the talk, supporting local design and production."
And Starnes said despite the whirlwind few weeks since the election Ardern took the time to say thanks.
"Something that tells you what type of person Jacinda is, even during how incredibly busy she must have been over the last few weeks she sent the team a thank you card."
Murray Bevan at fashion PR company Showroom 22 said Ardern was genuine with the support she gave New Zealand designers.
"She has always worn New Zealand designs and has specifically asked for designers Harman Gruisa and Ingrid Starnes who make their clothes in New Zealand," Bevan said.
Bevan said it was harder for high profile males to leave such an impression with a suit and tie although former Prime Minister John Key made the news for one of his suits.
Key was a fan of suits from RJB Design with owner Ronald Biddick making him a suit with Greenstone "washed into the weave."
Bevan said other politicians were proud to wear New Zealand designs and said National MP Nikki Kaye wore Ingrid Starnes and Paula Bennett loved footwear by Kathryn Wilson.
Associate editor at Viva Zoe Walker said it was significant and exciting that Ardern continued to support local designers.
"Policies and what she achieves in her new role are considerably more important than what she wears, but Jacinda is making a deliberate choice to support local creatives, the fashion industry and, importantly, businesses by wearing these items," Walker said.
"The majority of the garments are New Zealand made too, so she's spotlighting local manufacturing - which I know is something important, and motivating, to the designers she has worn.
"Jacinda is now the most visible person in New Zealand, so her choices - in what she does, says, buys, and yes, wears - do stand for something," Walker said.
