The Australian Bureau of Statistics has not fully implemented all lessons from its 2016 Census failures, a new report has found.
The auditor-general on Thursday released a report into planning for the August 2021 Census.
The last national survey was dogged by an online debacle that saw millions of people locked out of the website.
The ABS shut down the site over fears it was being hacked.
The auditor-general found planning for the 2021 survey was "partly effective".
"The ABS has not put in place arrangements to ensure that improvements to its architecture framework, change management processes and cyber security measures will be implemented ahead of the 2021 Census," the report found.
The bureau accepted all seven recommendations from the audit, saying work had already been done to put in place "the technology and security components necessary for a high quality 2021 Census".
"This includes rigorous independent testing and assurance of Census systems in line with the recommendations made in the report to ensure the maintenance of data quality, privacy and security," the ABS said.