The Labor frontbencher Andrew Giles says the inevitable postmortem from the 2019 election needs to be broader than examining whether the electoral system is delivering for voters. It also needs to consider questions of accountability and trust.

Giles, the opposition spokesman on cities and urban infrastructure and a former deputy chair of the joint standing committee on electoral matters, told a seminar at the University of Melbourne that policy agendas meant little to voters in 2019 “if no one believes it could ever be delivered”.

“What’s the point, fundamentally, of all our campaigning if it’s met with a resigned cynicism at best, or outright rejection at worst,” Giles said.

“We need to think about who’s participating, and how. We need to think about whether all Australians’ concerns are reflected and represented. We need to think about who’s not involved – whether by choice or by having been excluded.”

The challenge was not so much executing a technical review but arriving at an understanding of why people were alienated from the system: “I believe that the challenge is to reinforce and rebuild electoral and political institutions which support trust and confidence in our democracy.”

His comments come as the joint standing committee on electoral matters is inquiring into the conduct of the election, and Labor has urged the committee to investigate specifically whether the digital behemoths are having a negative impact on Australian democracy after Facebook refused to take down fake news about the “death tax” circulating during the May election campaign.

He hoped the committee could make useful suggestions at the end of its inquiry if it was prepared to ask the right questions, and said that during the last parliament it managed “to reach significant agreements on a multi-partisan basis”.

But fixing deficiencies in the system required politicians to understand trust and confidence was waning in democracies around the world, including Australia, for a range of reasons.

“Our accountability framework simply isn’t what it should be,” he said. “The very notion of a truly independent public service providing frank and fearless advice to government is under siege. Our freedom of information laws have become something close to a joke.

“In this age of big data, it’s getting harder and harder to obtain information about government decision-making. On a closely related note, the other declining institution we need to think about is the news media.”

There had been considerable attention in recent weeks on press freedom, he said.

“Threats to press freedom and the public’s right to know are critical, but [are] only part of the problem,” he said.

“Our democracy rests on shared understandings – being able to share in a national conversation. I’m worried that the fragmentation of our traditional media, the pressures on journalists and the practice of journalism, as well as the encroachment of the social media giants, has eroded our capacity to carry on this conversation.

“Curated news consumption narrows our understanding of the world, and diminishes our capacity to engage in meaningful debate. Without restoring a genuine national conversation, I fear any other reforms to our electoral or political institutions may prove worthless”.

He hoped the committee would look at nuts and bolts, like recommending real-time disclosure of donations with an appropriate disclosure limit of $1,000, and consider expenditure caps.

“The extraordinary role of Clive Palmer in May’s election demands a response,” he said.

“A billionaire spending $60m is a powerful reminder that the problem isn’t just about party fundraising and disclosure. It’s about dealing with an understanding that our politics can be purchased.”

Giles said the other side of that coin was “the sense of alienation felt by too many Australians”.

“Let’s think about those not enrolled to vote, those who didn’t vote, and those whose ballots reflected frustration not inspiration,” he said.

“Let’s not lose sight of the main game here: restoring confidence in the possibilities of Australian politics [and] developing and committing to an institutional framework that we can all have faith in.”