Keown said he had suggested the idea to the council "several times".
Making bus travel free would give the council an indication of whether the public actually wanted to use the system, he said.
At the moment "the numbers say no".
Keown said the use of buses had dropped from 4 percent to 2 percent of the city residents. Meanwhile, the council had spent in excess off $200 million to upgrade facilities and create new bus lanes.
"It just doesn’t make any sense."
The focus should be on getting more people on buses rather than spending money on upgrading the facilities.
Despite the numbers dropping, the overall feel towards the bus facilities from the public was positive.
Cr Keown said while there is no official timeline for this experiment he said "the sooner the better".