Federal Attorney-General Mark Dreyfus says it's embarrassing Queensland Premier Campbell Newman is at odds with Canberra over royal succession plans.

Leaders at the Commonwealth Heads of Government Meeting (CHOGM) in Perth in 2011 agreed in principle to change laws relating to Britain's succession.

A monarch's firstborn son becomes heir to the throne under current laws.

In anticipation of the birth of Prince William and his wife Catherine's first child, proposed changes would allow a firstborn girl to automatically become heir ahead of any younger brothers.

Prime Minister Julia Gillard has called for the states to pass legislation to allow the Commonwealth to make changes to succession.

But Mr Newman has said each state should pass its own legislation.

The federal attorney-general says he's "baffled" over why Mr Newman would want to engage in his own "legislative frolic".

"We will be the laughing stock of the Commonwealth nations if every Australian state tries to pass its own substantive succession laws," Mr Dreyfus said in a statement on Thursday.

"The last time I checked, we hadn't reverted to a collection of colonies."