They are understood to be historic infections, so they won't have to isolate and can fly back to New Zealand when the group heads to Japan on Wednesday.
Ardern remains Covid-free, which she had to be in order to enter the Istana - the presidential residence where she is having bilateral talks with Singapore Prime Minister Lee Hsien Loong later today.
She also needed a negative test before being allowed to fly to Japan, where she will have bilateral talks with her Japanese counterpart Fumio Kishida.
Ardern arrived yesterday on a RNZAF Boeing 757 flight and was greeted at the airport by Indranee Rajah, Singapore's Minister in the Prime Minister's office.
She spoke briefly this morning at a breakfast panel on digital disruption and a digitally enabled recovery, saying that some studies showed five years' worth of technology-based innovation happening in the first year of the pandemic.
"The pandemic has taught us all the importance of resilience and innovation in the face of adversity. Creativity and an entrepreneurial spirit will drive us to solve the challenges created by climate change, ensuring a safer, more sustainable future for us all," Ardern told an audience of business leaders.
"AI, machine learning and cloud computing represent just a few technologies that can be utilised to improve energy efficiency, water management, and enhanced food supply chains.
"That's why despite the challenging time that both our countries have been through, it is also an exciting time for Singapore and New Zealand to be rekindling connections and fortifying international partnerships."
Ardern is being accompanied on the trip by partner Clarke Gayford, Trade and Export Growth Minister Damien O'Connor, and a 12-strong trade and business delegation who are all heading to Japan on Wednesday.
Everyone in the delegation, Ardern included, did a PCR test last night and she will need a negative result before being allowed into the Istana.
A negative result is also needed before she can head to Japan on Wednesday,
The trip's main message is that New Zealand, having been isolated for much of the pandemic, is open for business and tourists.
A number of agreements to boost food exports and develop sustainable energy are expected to be announced.
Ardern is scheduled to have a courtesy call with Singapore President Halimah Yacob before attending a gala dinner tonight.
Trade with Singapore has surged in recent years and Singapore is now New Zealand's fifth biggest trading partner, right behind the fourth biggest, Japan.
