An Indigenous women's rugby league player in Australia has been fined and hit with a one-match ban for criticising Queen Elizabeth II.

Caitlin Moran, a 25-year-old who plays for Newcastle in Australia's National Rugby League Women's premiership, joined censored critics of the monarchy from around the world this week after she labelled Queen Elizabeth II a "dumb dog" in a since-deleted Instagram post. 

The post became the subject of an investigation by the National Rugby League's (NRL) Integrity Unit, which on Tuesday saw Moran become the first player in women's league history to receive a match ban related to off-field behaviour. 

She will also have to pay a fine equal to 25 percent of her salary, which would only be suspended if she completes training on the "appropriate" use of social media.