There have already been 56 conferences booked in for 2015, the Brisbane City Council said. There were 62 conferences in the city for the whole of 2014.

About one third of this year's delegates will come for the 2015 EduTECH National Conference & Exhibition in June, an event which Brisbane has hosted for several years.

The Brisbane Convention & Exhibition Centre will play host to several international medical conferences, including the Asia-Pacific Autism Conference, the International Conference on Acoustics, Speech and Signal Processing, and a 2500-person conference hosted by the World Gastroenterology Organisation.

November's G20 Summit had an estimated $400 million price tag, with the cost split between the federal, state and local governments.

Cr Quirk said Brisbane had generated nearly 30 strong leads for business events since the G20 and Global Cafe, and they could potentially have a $30 million economic impact on the city.

"Although it can take several years from initial bid to signed contracts, there are already strong conference bookings in the pipeline for this year as a direct outcome of the G20 and Global Café," Cr Quirk said.

"As a result of bids generated by Brisbane Convention & Exhibition Centre in collaboration with Brisbane Marketing's Convention Bureau, we already have future conferences such as the Asia Pacific Stroke Conference (APSC 2016) and International Congress of the International Federation of Translators 2017 in the bag.

"Current bookings alone indicate that the Brisbane economy will benefit from an average of 300 hotel room bookings each week thanks to the growing convention market."

Conferences held in Brisbane increased from 2013 to 2014 during the lead-up to the G20.