NSW Police were called to a crash near Glen Innes, four hours southwest of Byron Bay, on Wednesday afternoon.
Senior Sergeant Brendan Wiblen, 58, had been attempting to overtake another motorbike rider, when he lost control and crashed down an embankment, police said.
He died at the scene.
The serving Queensland officer was participating in the 2024 Wall to Wall ride, an annual charity event to commemorate the sacrifice of police colleagues.
Queensland Police Minister Mark Ryan said he was struggling to come to terms with the loss.
"It is almost beyond comprehension that this off-duty officer should lose his life just as he is engaged in a memorial event in honour of other fallen police officers," he told parliament.
"I know that the police family will offer them every support and I know too that there will be every support for the officer's colleagues and friends who were riding with him."
Sgt Wiblen began his career with Queensland police in 1996, spending 28 years in various roles including as the officer in charge at Southport station.
South Eastern Region Assistant Commissioner Brian Swan said the sergeant would be remembered for his quick wit and attention to detail.
"Our thoughts are with Brendan's loved ones, who are dealing with this tragic loss," he said.
"The police family stands together in grief and will continue to support Brendan's family during this unimaginable time."
Queensland Police Commissioner Steve Gollschewski also expressed his devastation and support for the family.
The Queensland Police Union said support was being arranged for Sgt Wiblen's loved ones, including financial assistance.
"Our mate left Brisbane this morning and had been in good spirits with friends and fellow riders before heading off on the first leg to Armidale," the union said in a statement.
Devastated to hear an off duty Queensland police officer has died during the Wall to Wall memorial ride near Glen Innes.— Steven Miles (@StevenJMiles) My deepest condolences to family, friends and all members of the Qld Police Service.Our thoughts are with you at this tough time.September 11, 2024
Premier Steven Miles said he was devastated to learn the news.
"Devastated to hear an off-duty Queensland police officer has died during the Wall to Wall memorial ride near Glen Innes," he said in a post on social media platform X.
The rest of the officers will arrive in Canberra on Saturday, where colleagues from other states and territories will join them for a day of remembrance.