A third of ASB customers had at least $10,000 in savings, up on a year ago, with 4 per cent of customers crossing this savings threshold during the pandemic.
However, the latest data for February 2021 also shows nearly half of customers have less than $1000 in savings.
Vittoria Shortt, ASB chief executive said the past 12 months had been very challenging for New Zealanders.
"It is good to see that collectively our financial wellbeing has held up surprisingly well."
But she said there were warning signs beneath the surface.
"We know we are not out of the woods yet, there are more Covid-19 effects to roll through the economy and this research highlights some concerns.
"The fact that more than a third of people have less than a single week's expenses available to them and almost half have less than $1000 in rainy day savings rings alarm bells for me. This puts them in a potentially vulnerable position."
Shortt said it wanted to use the information to help people become more resilient when events happened.
"Because we all know they are happening more frequently. So whether it is a pandemic, earthquake, global financial crisis - there are a lot more events occurring which create these really challenging conditions."
She said the bank helped people to save through its app by allowing them to round up the change which was seeing people save an average of $4m a month.
"Then we have got larger actions - going to have series of supporting tools so that people can focus on their financial wellbeing irrespective of what is going on in the moment."
She said lockdown meant people didn't or couldn't spend as much.
"We know that will reverse to a certain extent as lockdowns are less frequent and borders open but it is really about people's long term financial wellbeing."
One of the insights from its research on saving was the importance of people's attitudes towards savings.
"If you think about previous generations they were very frugal and they were frugal because they went through experiences that meant they needed to be. So it is really about attitudes towards money. And we think we need to help get back to some of those great basics around how you save, what you are spending on, try to balance those out in a better way that is happening at the moment."
"We have some people who earn quite a lot of money who don't have the level of resilience that they should or could."