It is up to individual banks to decide how much money they will allow to be deposited via their ATMs.
Smart ATMs take deposits and count the cash instantly allowing the money to show up quickly in a person's account. Normal ATMs may take a day or more for the cash to be counted and credited to an account.
The Reserve Bank warned in April that it sees smart ATMs as a high risk for money laundering.
"The ease of use and anonymity afforded by these services are considered to present a high level of ML/TF [money laundering/terrorism financing] risk for retail banks.
"This type of service has been highlighted both domestically and internationally as an area of concern," it said.
"While RBNZ recognises that this service provides greater customer convenience and quicker deposit of funds, the deposit of cash by unidentified persons remains a key vulnerability of this service."
On Tuesday the Reserve Bank sent a series of questions to banks asking them about smart ATMs and deposit limits.
A Reserve Bank spokesman said the survey was part of regular ongoing work with the institutions that it supervised.
"This work includes topical issues."
New Zealand's banks appear confident they are on top of money laundering risks.
Barbara Chapman, chief executive of ASB, which is owned by CBA, last week said the bank had re-examined its reporting processes and found no evidence of any problems.
"From where I am I'm quite comfortable with how we are responding."
ASB bank has confirmed it operates a different model of smart ATMs to its parent company CBA, with different software.
The bank has operated smart ATMs in New Zealand for three and a half years.
A spokesman said the maximum amount of funds able to be deposited by an unverified person was less than $10,000.
BNZ's chief risk officer Peter Whitelaw said its smart ATMs restricted cash deposits to an amount significantly below the threshold where customer due diligence may be required.
"For security reasons, we'd prefer not to give that exact amount. In addition, all transactions that go through our smart ATM's are subject to BNZ's transaction monitoring system, that identifies patterns of unusual or suspicious activity," Whitelaw said.
The bank undertook regular reporting and oversight on the transactions made via its smart ATMs, he said.
"BNZ is continually improving and refining its AML/CFT programmes as risks and typologies evolve."
An ANZ spokesman said it had a $5000 per transaction cap on deposits into its smart ATMs.
"ANZ has systems in place to ensure it complies with anti-money laundering obligations including processes to monitor and report suspicious activity.
"We are also subject to continuous supervision from RBNZ. ANZ also complies with its obligation to conduct customer due diligence."
A Westpac spokesman said its deposit limit was $6,600 per transaction.
"Westpac also has processes in place to identify any transaction that may be relevant to money laundering and report such transactions to the NZ Police Financial Intelligence Unit as required under the AML/CFT Act."
A Kiwibank spokeswoman said it didn't take deposits through its ATMs.
