The Commonwealth Auditor-General will review federal funding for the controversial WestConnex road project in Sydney.

The multibillion-dollar project will widen and extend the M4 and M5 motorways, linking them via tunnels from Haberfield to St Peters in Sydney’s inner west. It was to cost $11 billion under 2012 estimates, but by 2015 the price tag had ballooned to $16.8 billion to fast-track the project and…