Monarchists demand premiers apologise

Monarchists want state premiers to apologise for publicly backing a republic and are outraged the Queen's 90th birthday won't be "properly" celebrated.

Monarchists are demanding state premiers apologise for declaring their support for an Australian republic earlier this year.

The Australian Monarchist League is also angry that Australia won't be "properly" celebrating Queen Elizabeth's 90th birthday in June.

They've received a letter from Prime Minister Malcolm Turnbull explaining a stamp will be issued while Governor-General Peter Cosgrove will celebrate with the Queen in London but the group insists that isn't enough.