No progress has been made in reducing a massive backlog of overdue road maintenance in Western Australia, with Main Roads only reacting when the need becomes critical, the auditor-general says.
According to a report released by Colin Murphy, the maintenance backlog was $820 million in 2009 and has crept up to $845 million.
Mr Murphy said the figure was likely to stay high given minimal effort with preventative maintenance.
"Although Main Roads has done some preventative resurfacing on parts of the network, overall the approach to maintenance is still reactive - it's done when it becomes critical," Mr Murphy said.
Such an approach did not offer good value for money because critical maintenance was more complex and cost more, he said.
"If Main Roads continue with business as usual there is a significant risk that the state road network will continue to deteriorate and the backlog will rise," Mr Murphy said.
In 2009, one-third of WA's road network was older than its 40-year design life, but 46 per cent now fits that category.