Gert Bouwman said online personal and other loans could soon be offered by RaboPlus, which had taken deposits of $200 million since it opened for business in February.
Some of that online money had come from Rabobank's existing rural borrowing customers, but as much, if not more, had come from new customers, urban and rural.
"We have to do more research, but a real possibility is extending our online business into lending as well," said Bouwman.
He said Rabobank's "online-only" business in New Zealand had been modelled on similar initiatives in Belgium and Ireland.
The bank was also benchmarking the future growth of its New Zealand online business against its European initiatives.
He said the Irish online business had taken in nearly C750 million ($1.56 billion) after opening a year ago.
AdvertisementAdvertisementRabobank's online business in Belgium now had C1.5b ($3.1b).
Bouwman said early success for RaboPlus was being driven by one of the highest interest rates - 7.35% - on offer among a new breed of online savings accounts.
Rabobank could also offer investors an unequalled Triple A credit rating and a level of security unequalled in New Zealand.
This involved a digital signature being attached to every transaction which stopped fraudsters accessing accounts during the course of a transaction.
It took security levels beyond two-factor authentication, which uses electronic tokens with seemingly random identity numbers, but which was no longer regarded as a panacea.
Bouwman said online security was a far bigger issue in Europe than it had been in countries such as New Zealand and Australia, and technology in Europe had developed accordingly.
"Through RaboPlus we have bought this technolgy to New Zealand," he said.
Another possible development for RaboPlus was a greater offering of managed funds.
So far it has been offering its online customers managed funds from AMP, Asteron and Tower.
But that range might be extended as the online business grew, he said.
RaboPlus also offers term deposits.
RaboPlus is the latest in a growing line of high-interest earning online savings accounts, started in New Zealand by Superbank in 2004.
Many mainline banks have now followed suit, and have found the online savings accounts a quick way to access money.
Superbank, which is up for sale, quickly amassed deposits of $250m.
ASB Bank's SuperSaver grew from nothing to $2b in nine months and half that amount came from existing customers.
Rabobank is a giant global bank based in the Netherlands. It has built assets of $4b in the rural lending market since arriving seven years ago.
Bouwman said Rabobank had no plans to open branches and operate in the wider retail market.