They were likely to be there until the end of the week, police said.
Police would now like to speak to anyone who may have seen the two bicycles over the weekend, Detective Inspector Kevin Burke said.
"These bicycles are quite unique and we believe that they have been taken from the victims address in Second Avenue."
Meanwhile a 16-year-old male has been arrested and charged with Mr Griffin's death.
He appeared at Whangarei Youth Court yesterday and was remanded in custody until later this month.
Police said they would like to speak to anyone who may have seen the bicycles, or people riding the bicycles, between 6pm on Saturday October 4 and midday on Sunday October 5, in the Avenues or in the vicinity of the Bowling Club in Whangarei.
Anyone with information can call Crimestoppers on 0800 555 111.
The missing bikes: