The date also marks the last day of the current Dewan Rakyat sitting.
PH lawyer Michelle Ng said High Court judge Azizah Nawawi had fixed the afternoon of April 5 for the hearing on an urgent basis.
“We expect Parliament to be dissolved soon,” she said, adding that the PH legal team expected the RoS to file its court papers for the hearing by next week.
DAP legal bureau chief Gobind Singh previously said the High Court decision, after the full hearing, was important to PH as it had to prepare for the 14th general election (GE14).
The 2018 Dewan Rakyat session, expected to be the last sitting before GE14, started on March 5 and will end on April 5, although Parliament can be dissolved earlier.
The controversial redelineation exercise report presented to the prime minister by the Election Commission (EC) on new electoral boundaries is expected to be tabled and passed in the current sitting.
Critics say the new boundaries give the ruling Barisan Nasional the advantage but the EC denies this.
PH filed a judicial review last month in a bid to compel the RoS to register it. The opposition pact was granted leave by the court earlier this month to initiate a judicial review to challenge the RoS.
On Feb 21, PH filed an application for various orders against the RoS in a bid to compel the government agency to respond regarding its registration application.
Gobind had said that when an application was filed, the applicant had a legitimate expectation that the RoS would consider their application and respond.
“We do not see any reason for the RoS to withhold the registration of PH,” he added.
The action was jointly filed by PH chief secretary Saifuddin Abdullah, DAP secretary-general Lim Guan Eng, PKR secretary-general Saifuddin Nasution, PPBM secretary-general Shahruddin Salleh and Amanah deputy secretary-general Abang Ahmad Kerdee Abang Masagus.
The formation of PH was announced last year. It comprises PKR, DAP, Amanah and PPBM. The parties are planning to contest GE14 under a common banner.
Last month, the coalition named former prime minister and PPBM chairman Dr Mahathir Mohamad as its prime ministerial candidate should it win federal power in GE14.