The PN has backed calls for six more magistrates to be appointed to help cope with an ever-increasing workload.
The party urged the government to heed recommendations by the Association of Judges and Magistrates to increase the number of magistrates to ensure the criminal justice system continues to function effectively.
The government has issued a call for four new magistrates, but this follows the retirement of one and the appointment of two others as judges.
In a statement on Saturday, the PN said magistrates' workload was continuously increasing due to complex inquiries and a higher volume of cases.
Reforms in rent law, it added, would further increase pressures on the Rent Regulation Board, which is normally presided over by a magistrate.
The PN called for a "real and significant" increase in the number of magistrates and for the government to dedicate more resources to court to address problems of staff shortages.
"The government must appreciate the importance of the justice sector to the rule of law, and constraining it is therefore a serious threat to this principle," the PN said.