Labor's Queensland branch has confirmed it sent the text messages, which urged people not to vote for the Coalition. A spokesman said they had not intended to make them appear to be from Medicare, only to indicate this was the subject of the text message. Attorney-General George Brandis Credit:Andrew Meares Attorney-General George Brandis said on Sunday that the text messages and replica Medicare cards sent by the Australian Council of Trade Unions this week calling on voters to preference the Coalition last both seemed "to be prima facie breaches of the law". "I understand the Liberal Party or at least one of the state divisions has made a complaint to the police," he told Sky News.

A spokeswoman for the Australian Federal Police confirmed it received a referral regarding text messages on election day, but would not say who made it. Fairfax Media has been told police are assessing the complaint to decide whether any crime has occurred. "This matter is now being evaluated and whilst this occurs it would not be appropriate to provide further comment," the spokeswoman said. Senator Brandis would not rule out the Turnbull government also moving to intervene on the issue, saying "I think at the moment that's all this is." The Commonwealth Electoral Act makes it a crime to "print, publish or distribute, or cause, permit or authorise to be printed, published or distributed, any matter or thing that is likely to mislead or deceive an elector in relation to the casting of a vote." This includes telephone messages.

Convicted offenders can be fined up to $1000 or imprisoned for up to six months or both. Body corporate offenders can be fined up to $5000. The Australian Electoral Commission says on its website this law is aimed at political messages that try to influence how ballot papers are marked, rather than voters' choice of candidate or party. It said that under current law it was not responsible for complaints about such messages. Mr Turnbull declared the text message "an extraordinary act of dishonesty" on election night. "No doubt the police will investigate," he added.