Federal member for Cunningham Sharon Bird and state Labor spokesman for the Illawarra Ryan Park say $8.1 million was announced in March 2013 to upgrade the existing northbound parking bay on the M1 Princes Motorway (Mount Ousley Road).

More than two years on, the underwhelming area of bitumen near Clive Bissell Drive sits unchanged.

Ms Bird and Mr Park said NSW Minister for Roads Duncan Gay had to "come clean" about construction delays and confirm when construction would begin.

On Monday, the politicians stood just metres away from the truck stop's sole portaloo as they spoke of their concerns, while a close-to-capacity parking area behind them reinforced the message.

"We have had this truck stop for years and years, it's very basic," Ms Bird said.

"We were told at the end of last year that construction would have commenced in the first half of this year and as you can see, it's far from having commenced."

The planned upgrade would increase the truck stop's capacity from four to between 10 and 15 B-double bays, along with the addition of toilets, shade/shelter and rubbish bins.

Mr Park said the infrastructure would allow truck drivers and tourists who used the route to be able to "take a break, get a rest and drive safely".

"We know that this is one of the largest freight corridors in the country, we know with the expansion of the port at Port Kembla there will be a large number of trucks continuing to use Mount Ousley," he said.

"This is a project that needs to get on with it, this is a government that needs to get on with it."

TWU Illawarra secretary Nick McIntosh admitted an upgrade was needed, but said it would mean little to the drivers in some heavy vehicles banned from using it by Wollongong City Council and the National Heavy Vehicle Regulator (NHVR).

"I think the problem's worse than a lot of people think. I've got a lot of TWU members who deliver coal ... they've got to go up Mount Ousley and they use vehicles that are known as A-doubles [slightly longer than a B-double and can carry more weight]," Mr McIntosh said.

"Not only are we saying it's too small generally and the facilities are inadequate, but some of our guys [driving A-doubles] have actually been banned from using the truck stop. That's a huge problem for us because it obviously impacts on their fatigue management ... these guys are 12-hour shift workers."

A spokesman for the council said an application was received via the NHVR to approve the A-double trucks using the section of Clive Bissell Drive between the truck stop exit and Mount Ousley Road.

"Council has refused this request based on safety issues."

Minister for Roads Duncan Gay has revealed work on the Mount Ousley truck stop upgrade won’t begin until May next year.

Mr Gay said $3.5million for the upgrade was included in the 2015-16 budget as part of the government’s heavy vehicle safety productivity program.

Mr Gay told Parliament last week planning work was ‘‘well under way’’ and detailed design work was continuing.

‘‘Key stakeholders, including heavy vehicle transport operators, the Port Kembla Port Corporation and the Wollongong Lions Club that operates those terrific driver reviver services at the location, participated in a project workshop in early June,’’ he said.

‘‘Roads and Maritime Services will... keep the community and industry informed.’’