The electoral watchdog has received complaints about marriage survey "no" case skywriting over Sydney on the weekend not being properly authorised.
A grassroots campaigner against same-sex marriage commissioned a pilot to write "Vote No".
The skywriting, which was not organised by the key "no" case group Coalition for Marriage, attracted much discussion social media, and the website from which it was crowdfunded was inundated with comments.
The Australian Electoral Commission has received a number of complaints regarding the skywriting.
But an AEC spokesman told AAP on Monday the "safeguards" laws passed by parliament did not apply to this type of communication.
"It is only material that is capable of containing authorisation details that is regulated by the Act," the spokesman said.
Prime Minister Malcolm Turnbull, who is encouraging a "yes" vote, told reporters people were entitled to express their views.
"If you want people to respect your point of view you've got to be prepared to respect theirs," Mr Turnbull said.
The Coalition for Marriage updated its website over the weekend to comply with the need for authorisation under the safeguards laws, but won't face any penalty.
"As the legislation only came into operation late last week and the website is now compliant, the AEC does not propose to take any action," the AEC spokesman said.
