Rooftop gardens and bars may no longer be counted as an entire storey in new developments as Brisbane City Council progresses legislation changes in a bid to encourage more green space.

The council decided to progress a major amendment to its City Plan at Tuesday's council meeting to encourage more rooftop gardens and vertical green spaces in new developments, by no longer counting rooftop green space as an entire storey.

Lord mayor Adrian Schrinner told the chamber it was good to see the tops of buildings previously only used for equipment transformed into green spaces and pool facilities to help take advantage of Brisbane's climate.

The conditions would include a minimum of 15 percent of the rooftop covered in landscaping and rooftop gardens that were not a private space, or solid shade structures, a pool or spa.

A maximum of 30 percent of the rooftop could be used for roofed structures, and 15 percent for fully enclosed structures such as showers, toilets or other equipment.

A condition was also included allowing a structure for a bar or food and drink outlet if the development was in a mixed-use zone.

"Rooftop gardens play an important role in the streetscape of Brisbane, particularly in the inner city and where there is high-density development," Cr Cook said.