Mr Gunner became unwell on Friday morning at the Bombing of Darwin Day commemoration, where he gave a 10-minute speech to about 1500 guests at the city's Cenotaph.

"The chief has had the test and is isolating while waits for the test results," an NT government spokeswoman told AAP.

"There's probably nothing to worry about and he's following the health advice."

Conditions at the commemoration were hot and humid for guests in formal attire. The city reached a maximum temperature of 31C.

While you're with us, you can now receive updates straight to your inbox each Friday at 6am from the Katherine Times. To make sure you're up to date with all the news, sign up here.