Labor's reclaiming of a key western Sydney seat at Saturday's federal election this week inspired elation but was followed by rebukes about whether the party won either with a scare campaign or by coasting to victory.

Labor's narrow win in the Penrith-area seat of Lindsay confounded its internal polling and drew conflicting stories about how much the party actually spent on the seat and whether it won on effort or circumstance.

But a far more interesting issue is one of the major reasons voters chose to leave the Liberals and one that featured prominently before hardcore efforts had begun. And it potentially heralds bad news for the Baird Liberal government.

Sources in both parties complained their Lindsay campaigns were under-resourced after early polls had it as an easy hold for the Liberals.

Some leaked documents suggest its residents received fewer door knocks or phone calls that bothered residents in other seats that proved much safer.

So, left comparatively on their own, what was the primary issue on these voters' minds?

Just over a week after the election was called, for nearly a third of Lindsay residents, it wasn't company tax cuts, economic ties with China or plans for future innovation. In fact, it wasn't an issue under the federal government's control, according to an ALP poll.

It was the dire state of the emergency ward at Nepean Hospital and the need for money for an upgrade. Medicare was in second place with about 20 per cent.

As Labor's national messages grew louder, the two issues are understood to have broadly swapped places on polling day but hospital funding figured in many other contests.

It was the NSW government's call not to upgrade Nepean. But given recent disputes over funding this seems like a less egregious example of voters taking their anger out on a federal party for state policy.

But it is bad news for the state Liberals.

It is perhaps an irony to quote the same local party research that has been proved unreliable this campaign.

But as Labor stalwart Bruce Hawker said this week, without research you have only your gut and serious trouble.

Even if these polls are out by half (which is unlikely), if these are the issues on which voters are making decisions already, the NSW Liberals are in a bind.

The state seat of Penrith and a handful of others overlap with federal divisions in which the Liberals lost ground on Saturday. They came into the fold in 2011 and resisted a 2015 state Labor scare on electricity campaign.

But while hospital upgrades featured hugely in Baird's election campaign with $5 billion of funding and 60 individual announcements, they literally cannot come fast enough.

Certainly not for voters in Lindsay, who presumably saw $1 million set aside for "planning" for the hospital at last month's NSW budget as inadequate relative to a $400 million upgrade.

But credible reports of crisis have been made about other Sydney hospitals, especially in times of stress such as winter.

The Herald reported last year that a two-day wait for a ward bed had become the norm at Blacktown Hospital. The first of many stages of redevelopment of that and a partner hospital was completed in May for $320 million.

They cannot all be built at once.

Sydney University Associate Professor of Emergency Medicine Paul Middleton has spent 16 years in various Sydney emergency rooms.

He says a longer-lived and unhealthier population, demographic growth and problems with primary care are driving increased pressure on hospitals.

But he suspects the issue is at a tipping point. He says demand is continuing to rise across greater Sydney hospitals and estimates some yet to become hot political issues are seeing patient number grow by up to 10 per cent a year.

"It's an exponentially growing crisis," he said.

That is always good grist for an opposition.

But another lesson from recent federal campaigning is party strategists increasingly care more about what issue is being talked about than the argument behind it.

They leave it to voters with strong convictions about who is best to manage which policy area to join those dots. A day spent arguing about healthcare, then, was scored as a win for Labor, and the economy for the Liberals.

The state Labor opposition has its campaign theme three years early. And people seem to already be listening and receptive.

James Robertson is state political reporter. Sean Nicholls is on leave.