Prime Minister Robert Abela made a rare visit to the PN's headquarters on Thursday to pay his respects to Karl Gouder.
Abela, accompanied by his wife Lydia, led a delegation from the Labour Party that went to pay tribute to Gouder, who was found dead on Tuesday.
"Karl Gouder was a politician who was respected by all. He worked without ever harming anyone. This is a moment where we must insist on national unity," Abela said in a short note on Facebook.
He was joined by former minister Chris Fearne, party president Ramona Attard and PL CEO Daniel Micallef, who also took time to sign the condolences book.
The book is being kept open to the public between 9 am and 7 pm tomorrow.
The PN previously announced that Gouder's funeral would take place on Saturday at the St Julian's parish church. It will also be broadcast on NET Television.
In a previous tribute to Gouder, Abela said that he had been friends with him since they were both schoolboys and despite later in life finding themselves on the opposite sides of parliament, their childhood friendship nevertheless endured.
"Karl had a strong sense of duty to both his community and to citizens. I am truly sorry for his loss," Abela said.