An increasing number of women are complaining to the Human Rights Commission about being sacked because they're pregnant.

The commission says it's received 84 complaints in the past two years from women who have been sacked or treated differently to other employees.

"Unfortunately this is becoming far too common," commissioner Judy McGregor said on Tuesday.

"It's a persistent problem and the commission is making pregnancy and maternity rights a feature of its guidance for employers."

Labour MP Sue Moroney says it's illegal and underscores a lack of respect for workers' rights.

"With more women of child-bearing age working and increasing numbers of women being the household's primary earner there will be more women working while pregnant, and working further into their pregnancies," she said.