Those accountants are being targeted by CPA Australia, which is inviting NZICA members to join without having to pay fees until January 2015.
Accountants have to belong to either NZICA or another body, such as CPA Australia, if they want to become fully certified in their professional duties.
Alex Malley, chief executive of CPA Australia, said the free sign-up offer was "a fantastic opportunity" for Kiwi chartered accountants.
"The offer we've opened today is part of our continuing commitment to New Zealand, designed to consolidate our critical mass in the Asia-Pacific and continue our proud record of growth throughout our 127-year history," he said.
CPA Australia first established an office in New Zealand in 2005 and its local membership had grown by about 20 per cent in the last five years, Malley said.
The body offered "strong, local advocacy, education and training" to its Kiwi members.
But Hamilton accountant Bruce Sparrow - who is publically opposing the NZICA-ICAA merger - said he had also no interest in joining CPA Australia.
Sparrow is spokesman for a group of about 150 accountants who have called themselves Accountants Deferring the Decision (ADDs).
"We belong to the Institute (NZICA) because we value its place in society. It's New Zealand-based at the moment and we don't want anything to do with Australia," he said.
Sparrow said New Zealand accountants needed a New Zealand body, not an Australian one.
"The Australian tax system is completely different to ours, as is the political system.
We certainly need to bat for ourselves. The institute needs to be New Zealand-based."
While CPA Australia's offer of zero fees was attractive in the short term, it would ultimately leave Kiwi accountants represented by an Australian group, Sparrow said.
Members of NZICA have until October 30 to vote on the merger. If members vote in support, implementation of the so-called One New Institute is expected to begin next year.
To read an opinion piece on the proposal, written by NZICA chief executive Craig Norgate, go here.