In an email to existing customers, Amazon said under auDA policy, Gandi is not permitted to hide email addresses for .au domains, including .com.au and .net.au, from WHOIS queries.
"On April 24, your email address will no longer be hidden from WHOIS queries for your .au domains that previously had privacy protection enabled," it said.
ZDNet has contacted auDA for further comment to see if any other domain registrar are affected.
auDA recently announced the departure of CEO Chris Disspain, whose contract was due for renewal later this year. However, according to the auDA, the board agreed "new leadership was required to take the organisation forward".
"The Board acknowledged and thanked Mr Disspain, as founding CEO of auDA, for the hard work and visionary leadership he has demonstrated throughout his tenure, helping to cement the organisation's standing as one of the world's best practice ccTLD managers," the company said.
In the interim, auDA's current chief operations and policy officer Jo Lim has been appointed to the Acting CEO role while the company searches for a replacement over the next six months.