Bernard Grech accused Robert Abela on Sunday of having "something to hide" over his dismissal of calls for a public inquiry into the death of 20-year-old Jean Paul Sofia.
Sofia, 20, was killed in a building collapse on a Corradino construction site.
Times of Malta revealed how the government land on which the private factory was being built is leased to an alleged human trafficker, Kurt Buhagiar.
Last week, the Opposition tabled a parliamentary motion urging the government to launch a public inquiry into the collapse. Sofia's parents, meanwhile, wrote an open letter in which they blamed their son's death on inaction by state entities as well as those responsible for the construction site’s development.
On Wednesday, Sofia's mother, Isabelle Bonnici, went straight to MPs calling on them to support her call for a public inquiry into the incident.
Then, on Thursday, PN MEP Casa wrote to the Council of Europe’s Commissioner for Human Rights calling for scrutiny of the government’s persistence against launching an independent public inquiry.
Addressing PN radio listeners on Sunday, Grech said the prime minister was not only arrogant but also insensitive in this case.
"It is clear he has something to hide. If he did not have anything to hide, he would have called a public inquiry," Grech said.
Abela is afraid and weak, Grech said, adding that instead of choosing to side with the Maltese, with vulnerable and honest citizens, " he keeps siding with the criminals, fraudsters and murderers".
During the short radio interview, Grech also referred to Abela's address to parliament on Thursday, when the House debated a private members’ motion filed by PN leader Bernard Grech and PN MP Adrian Delia, seeking to force the government to sue Vitals and Steward for money received since the contracts deemed fraudulent were signed.
The controversial hospitals' privatisation deal was originally signed with Vitals, with the concession being handed to Steward Healthcare in 2018. A landmark judgment declared the deal “fraudulent” and ordered that St Luke’s, Karin Grech and Gozo hospitals be returned to the government within three months.
Steward this week appealed the judgment which annulled the concession.
On Thursday, Abela spoke for over an hour, largely in defence of Steward Health Care's time running the three state hospitals.
On Sunday, Grech said that during that speech, the prime minister had just equipped Steward with ammunition to win the appeal.
The Opposition leader also referred to a ruling by the Constitutional Court that confirmed a decision slamming PBS and the Broadcasting Authority for partiality in broadcasting.
Three weeks on, no one has shouldered any responsibility for the breach of rights of the PN, and, consequently, the breach of rights of the Maltese people, Grech said.