The Roads and Maritime Services undertook essential maintenance work on Appin Road in early April, periodically closing the stretch between Appin township and the M1 Princes Motorway over a three-day period while work was carried out.

Essential re-surfacing work was completed but the all-essential line marking was not.

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Roadwork signs still greet 10,000 daily motorists on a particularly bendy stretch of the notorious road.

Macarthur MP Dr Mike Freelander, who travels the stretch daily, has questioned whether the Roads and Maritime Services take safety on the road seriously.

He said the speed through the resurfaced section remained at 90km/h and was navigated frequently by trucks travelling to and from nearby mines.

The section in question also has a merge between two southbound lanes and is difficult to navigate during poor weather conditions.

Dr Freelander said the failure to provide line markings demonstrated a lack of understanding for how dangerous the road could be.

"It also demonstrates, on behalf of the state and federal governments, how poor their management has been of the money that has been allocated to improve it," Dr Freelander said.

"It's wasted on dribs and drabs without a commitment to fully fix the road. It's just a matter of time before something tragic happens again."

Dr Freelander said a Shorten Labor government, if elected next Saturday, would spend $50 million on safety upgrades to the road, along with $5 million for a wildlife bridge.

A Roads and Maritime Services spokesman said the line marking delay had occurred because of "issues with scheduling and availability of work crews" and was scheduled to occur week commencing Monday, May 13.

More than 20 people have been killed in accidents on the road since the year 2000.

Wollondilly mayor Mathew Deeth said his council wanted the Roads and Maritime Services "to lift its socks".

"We have been calling on the state government and the RMS to come to the table and solve the issue of Appin Road because frankly it's not good enough," he said.

"Appin Road is one of the most unsafe roads in the region, we need all parties and key stakeholders to come together and solve the issue."