Some of the state's best-loved destinations, including the Sydney Opera House and Taronga Zoo, have been blindsided by an order to dump their distinctive branding and adopt the NSW government Waratah as their logo.

A directive issued by Premier Gladys Berejiklian last month informed the state's most famous cultural institutions the Waratah was to be "the only brand identity" used on all communications including advertising and signage.

"Ensure consistency": Some of NSW's most famous institutions have been ordered to drop their own branding in favour of the Waratah.

That would involve ditching the distinctive logos used by government agencies, such as the Opera House, Taronga Zoo, Sydney Olympic Park, the Art Gallery of NSW, the Australian Museum and Barangaroo.

Senior current and former staff at the agencies privately indicated they were taken by surprise and were now scrambling to secure an exemption – with one suggesting it was "like an episode of Utopia", the ABC comedy series satirising government bureaucracy.