Major Brisbane traffic changes leading to delays of up to 50 minutes around the $380 million Go Between Bridge at Milton have been announced and will come into effect next month.

These changes include reducing the inbound and outbound lanes on Coronation Drive around the bridge's construction site near Hale Street from three lanes down to two lanes.

Traffic using the Riverside Expressway and heading towards the Inner City Bypass will have to use the left-hand lanes, not the right-hand lanes as they do now.

These changes around the Go Between Bridge, formerly known as the Hale Street Link, will run from November 1 for the next four months while the Coronation Drive overpass is built.

Brisbane City Council's deputy mayor Graham Quirk has defended the lengthy delays expected while the number of traffic lanes are reduced as a necessary difficulty to allow the bridge to be built.