Niree Creed, spokeswoman for the 85-year-old monarch’s representative in Australia, Governor General Quentin Bryce, says the ill staffer was taken by ambulance on Tuesday from the Canberra mansion where the queen is staying “for observation as a precautionary measure.”

Creed would not say what was wrong with the staffer. Australia’s Fairfax Radio reports it was an allergic reaction.

The queen laid a wreath at the national war memorial Tuesday on the seventh day of her 16th Australian visit.

She and husband Prince Philip will open a meeting of the 54-nation Commonwealth in the city of Perth on Friday.