It is now a different story for commuters searching for car parks at the station on the $1.8 billion South West Rail Link, Sydney's newest train line.

The 850 car spots at Leppington are often full by 10am, leaving motorists who arrive later to circle repeatedly to find a park.

"It has got a lot worse since [it opened]," Ms Chami said. "I was surprised they didn't build a multi-storey car park because it will probably get worse."

The surge in demand for parks in a short space of time at Leppington Station, which is still surrounded by paddocks, is illustrative of the challenges facing tens of thousands of commuters each week day across Sydney. They rush at ever earlier times in the morning to claim car parks near train stations.

In response to what it describes as a "parking crisis", the NRMA wants to mobilise its 2.5 million members to help free up unused spaces in driveways, garages and other spots near train stations.

The motoring group wants to team up with a parking operator to open up to its members the opportunity to earn income from leasing spots to other motorists, while helping solve a growing headache for commuters and transport officials alike.

"Around the transport hubs, there are probably tens of thousands of driveways and garages that lie completely empty during the day," NRMA chief executive Rohan Lund said.

"We are looking at how we use our membership base and our balance sheet to make sure we provide those parks. It is a big solution for what is a major problem out there."

At present, car parking disrupters such as Divvy, Parkhound and ParkMonkey tend to focus on inner-city areas, rather than outer suburbs where the NRMA wants to link motorists to vacant car spaces at homes and businesses.

"We are also looking at how we can value add to the parking experience with solutions like car servicing while the car sits unused in the parking station, or by encouraging and promoting car-share services," he said.

Mr Lund said one of the biggest barriers to people using public transport was a lack of parking near commuter hubs.

"We need look no further than the commuter car parks that have been built along the new South West Rail Link for proof. Demand has almost outstripped supply."

People tend to drive to stations the further out of Sydney they live, partly because buses to them are infrequent.

At Leppington, pressure for spots has skyrocketed since direct train services to Sydney's CBD began late last year. While the problem has not been as acute over the past two weeks, the end of the school holidays again increases demand.

"When it first opened, not many people used the station," said Austral resident and nurse Kim Kovac, who parks at Leppington and catches the train to work at the Red Cross in Sydney's CBD. "Now it fills quickly.

"Before long it is not going to be enough. I can just envisage the problem when the land is subdivided and there are 20,000 homes here."

Jocelyn Schankaran has also watched demand for car spaces surge since she moved to Leppington in November.

"This is going to get really chaotic because we have got houses going up every week," she said. "There are 25,000 people moving into Oran Park.

"I used to park in the section that faces the station at this time of the morning [at 7.30am]. Now I am almost down the other end."

Only about a fifth of the population in greater western Sydney lives within 800 metres – regarded as a reasonable walking distance – of a train station.

And at Penrith, fewer than 8 per cent of the population lives within a reasonable distance of major public transport, according to figures from the Western Sydney Regional Organisation of Councils.

The organisation said there would be little respite from the debilitating effects of traffic congestion unless more railway stations were built and there was greater density of homes and businesses around major transport hubs.

At Penrith, parking near the station is a major challenge not only for commuters but for local retailers. Commuters turn up early to nab long-stay parking, reducing the spaces available for shoppers later in the day.

A spokeswoman for Penrith Council said commuter car parking placed "enormous pressure" on the city centre, due largely to a lack of buses between the train stations and outer suburbs forcing people to drive. "We support any initiative that frees up, or creates, extra car spaces for commuters," she said.

The NSW government, which is responsible for commuter car parks, has provided more than 5800 new spaces since early 2011, and has plans for a further 7900 across the state.

A spokesman for Transport for NSW said 14 new car parks – nine of which were likely to be multi-storey buildings – were planned for greater Sydney over the next two years.

"We know that a lack of parking around train stations is a big issue for customers, which is why we are getting on with the job in the best way we know how: delivering more commuter spaces for customers across the public transport network," he said.