Taxpayers will have to pay compensation to the owners of WestConnex if there are any delays or changes to the interchange at Rozelle, according to an investor briefing disclosed to the ASX.

The state government announced last week that Transurban had won the bidding for majority control of the 33-kilometre WestConnex.

The Sydney Transport Partners consortium, led by Transurban, will pay $9.3 billion for 51 per cent of the motorway, which is due to open by 2023.

About $5.3 billion of the sale price would be spent delivering the final third stage of WestConnex, a tunnel under Sydney's inner west linking the M4 and M5 motorways.