Updated 6.29pm with PN statement.
Nationalist Party MP Karol Aquilina alleged on Wednesday that Prime Minister Robert Abela challenged him to a physical fight during Wednesday's parliamentary sitting.
Aquilina said Abela had challenged him "to meet outside and he will show him" [oħroġ barra u nurik] while the Speaker was handing down a parliamentary ruling.
"If the prime minister wants to fight, he can fight with a wall or find someone else to fight with," Aquilina said, adding that Abela - a former bodybuilder who regularly attends the gym - was undoubtedly stronger than him.
"Someone saying that in parliament is not on," Aquilina said.
Abela's challenge, Aquilina said, was especially worrying when considering that the prime minister has the power of the executive government behind him.
"The prime minister has the forces of order behind him and can order my arrest," he said. Aquilina said Speaker Anġlu Farrugia should have reacted to Abela's comment.
Farrugia said he would have acted, had Aquilina brought the issue to his attention.
Labour: A calumny and lie
In a brief statement, the Labour Party said Aquilina was lying with "infantile allegations".
"It is incredible how the PN's extremist faction continues to excel in creative lying and calumny," the party said, describing Aquilina as the Opposition's "de facto leader".
'Parliament being brought to disrepute'
Aquilina said the government is bringing parliament into disrepute and has demoted it to a "law factory".
He said the attendance in parliament is low, while some parliamentary committees barely ever meet.
"The health committee in parliament hasn't met for over a year; there isn't even a band club in Malta that meets so little," he said.
Government MPs also stage parliamentary questions for their ministers to answer, Aquilina charged.
"In the [UK] House of Commons, when a deputy coordinates with a minister, they call it 'arranged PQs'. They see that as an insult," he said.
PN: Abela is acting like a playground bully
The Nationalist Party said Robert Abela was continuing to act like a playground bully.
"Robert Abela and his colleagues seem to believe they are above public scrutiny. They are refusing to publish their asset declarations, which are now over a year overdue, and are now resorting to intimidation.
"That is exactly what bullies do," the party said.
"Our country and the Maltese people deserve a mature Prime Minister, not one who resorts to flexing his muscles whenever he is criticised.
"If there's anyone who is childish, it is he who acts like a bully in front of others, but then, when confronted, runs off crying and claims it's not true," the PN said.