More than four years after journalist Daphne Caruana Galizia was murdered in Malta, her family is still fighting for action to address the political corruption she exposed.

"There is still not enough of a deterrent towards organised crime and corruption," her son Matthew told AFP ahead of Saturday's election, in which the ruling Labour Party is expected to be re-elected.

Seven men have either been accused or admitted complicity in her murder, but he fears "the lack of a single conviction for corruption" will have a lasting impact.

"It sends a message to the wider public in a trickledown way that corruption is acceptable as long as you can get away with it," he said.

Caruana Galizia was speaking from the family's rural home near Bidnija, not far from where his mother's car was blown up on October 16, 2017, in a murder that shocked the tiny Mediterranean island nation.

A large photograph of her still marks the spot where the wreckage was found by the side of the road, while on a nearby tree, purple ribbons are tied to branches in tribute.

Before her death, she faced constant harassment for her work exposing links between top members of Labour prime minister Joseph Muscat's government and senior Maltese businessmen.

A public inquiry last year found no evidence of state involvement in her assassination, but found it created a "climate of impunity" for those who wanted to silence her.

Muscat resigned in January 2020, following public protests at his perceived efforts to protect friends and allies from the investigation, and was replaced by Labour colleague Robert Abela.

Abela has moved to strengthen the rule of law and better protect journalists, but Caruana Galizia says it does not go far enough.

The inquiry represented for Malta a "once-in-a-generation opportunity to go one way or the other, to look towards the past or look towards a future that is free from corruption," he said.

But he said it "needs to be followed through", warning "root and branch reform" is needed.

The inquiry found an "orchestrated plan" from the top of government to suppress Daphne Caruana Galizia's investigations, and condemned the inaction of institutions that should have followed up her work -- and protected her.

Abela has moved to limit the prime minister's powers over the appointment of judges and the police commissioner, and has charged a committee of experts to examine how better to protect journalists in Malta.

The government has also proposed legal changes to protect against so-called strategic lawsuits against public prosecution (SLAPPs) -- expensive, baseless legal proceedings used by the rich and powerful to silence journalists.

Matthew Caruana Galizia welcomed these moves, but said Abela "rejected anti-mafia and anti-abuse of power legislation out of hand, which is a bit disappointing."

Seven men have either been accused or admitted complicity in the murder of Daphne Caruana Galizia but her son says "the lack of a single conviction for corruption" will have a lasting impact
Seven men have either been accused or admitted complicity in the murder of Daphne Caruana Galizia but her son says "the lack of a single conviction for corruption" will have a lasting impact AFP / Matthew MIRABELLI

On the media, there were also many other issues to address, not least the fact that Malta's main parties own television channels and radio stations, which Caruana Galizia said "is strangling independent media".

Abela's dodging of reporters and refusal to give interviews hardly inspires confidence in his efforts to protect media freedom, he added.

Outside Malta's law courts in the capital Valletta, a shrine remains to Daphne Caruana Galizia, with candles, flowers and signs demanding "Justice for Daphne".

The economy has dominated the election campaign but many voters still evoke her name as a reminder of how much their country needs to do.

The opposition Nationalist Party has been pressing the issue, highlighted the grey-listing of Malta last year by an anti-money laundering body.

Russia's invasion of Ukraine also shone a spotlight on Malta's "golden passports" scheme, which offers citizenship to wealthy investors.

Under pressure, the government suspended it for Russians and Belarusians, but Caruana Galizia insisted: "The scheme needs to be scrapped in its entirety."

Malta's Chamber of Commerce rejects any suggestion that the country is widely corrupt.

But Matthew Caruana Galizia says "it's a problem across the board" -- and said nothing will change until Labour acknowledges the scale of what happened.

"The core of the Labour Party needs to be changed," he said.

The 36-year-old seems both energised and exhausted by his campaign, but insists the family will keep on fighting.

"My main concern is not revenge, it's the deterrent effect. We want to make sure that this never happens again, not just my mother's murder but the corruption that led up to it," he said.

Malta's government did not respond to a request for comment for this article.