A backlog of roads repairs has increased by more than $200 million in a year, bringing the total bill for outstanding maintenance in NSW to more than $5 billion.

The NSW opposition spokeswoman for roads, maritime and freight, Jodi McKay, said the maintenance backlog had doubled in three years. "Five billion dollars is a lot of potholes and cracked footpaths," she said.

Sydney traffic congestion on Epping Road during peak hour. Credit:Michele Mossop

"Motorists are spending more time stuck driving on rundown roads."

The NSW Auditor-General's latest transport report shows the road maintenance backlog has grown from $2.7 billion in 2012-13 to $5.1 billion in 2013-14 and $5.3 billion in 2014-15. The report also shows travel speeds have declined.