Commuters also face disruptions from full or partial closures of the busy M1 metro line over several weekends,as well as services stopping earlier some nights.
The globe-like structure will tower 30 metres when it is finished,making it visible to passengers when the first flights start late next year.
The $2 billion motorway is due to open ahead of the first passenger plane touching down late next year.
Excavation equipment has now churned through about a million tonnes of rock deep below the north shore,completing two-thirds of the entire project.
A delayed upgrade to the western end of the critical link has been boosted by $250 million in federal funding.
The state government will buy dozens of new buses in a bid to end long queues at stops along northern beaches and north shore routes.
A confidential Treasury analysis reveals the staggering cost of a major change to toll roads that had been recommended by a review.
The government awarded the Royal Bank of Canada a $4.1 million contract for its negotiations with tolling operators,the latest in a long history of consultants making big profits off the network.
Read our guide to the road closures,planned track work and night-time public transport for the Mardi Gras Parade.
Schoolchildren and parents are among commuters feeling the pain at bus stops during morning peaks as bendy buses are out of action.