The "Jacinda effect" has brought in more than $100,000 and 600 new volunteers for Labour in 24 hours, the party's new deputy leader Kelvin Davis says.
Mr Davis also said his selection as deputy on Tuesday - the first Maori to hold the role - had galvanised Maori.
"The support we have received in the last 24 hours has just been phenomenal," he told Radio New Zealand on Wednesday morning.
"The Jacinda effect has already kicked in. We've had ... over $110,000 donated to our campaign by mums and dads and Kiwis all around the country.
"We've had over 600 volunteers put their hand up and say they want to help out in our campaign. I'd like to think that's just the start."
General secretary Andrew Kirton confirmed the figures, and said the average online donation had been about $30.
Half of the donations came from people Labour had never heard from before, he said.
"We've never seen anything remotely like this. It was coming in at something like $700 a minute."
Labour now has between 3000 and 5000 active volunteers for its campaign.
Its change of leadership so close to the general election on September 23 has created new costs, in particular the need to update billboards and print new leaflets.
Mr Kirton said that would cost in the tens of thousands: "Five figures, not six figures."
The flood of donations to Labour was more than matched by two large donations declared by National yesterday, which totalled $168,000.
Those donations came from rich-lister and former owner of the National Business Review Barry Colman and manufacturing company Alpha Laboratories.
Davis said he believed Ardern had "cut-through" with women and young people, while he hoped that Kiwi blokes would relate to him.
"I'm the sort of guy that loves a beer at the RSA on a Friday, spends way too much time watching sport on the weekend when I should be mowing the lawns, and my most treasured possession is the Sky remote."
The new leadership team is taking 72 hours to assess Labour's campaign platform and decide about any major changes.
Ms Ardern said many of Labour's ideas already resonated, but she wanted to place extra emphasis on the importance of housing, health and education to reducing inequality.
She also hinted at changes in education, and would not rule out bringing forward the party's free tertiary education policy, which is set for a staggered introduction between 2019 and 2025.
