Deputy Chief Minister Datuk Amar Abang Johari also announced that all government departments, agencies and commercial sectors have been directed to fly the state flag at half-mast from Wednesday afternoon.
"The state government has declared tomorrow as a special public holiday to allow members of the public to pay their last respects at Masjid Jamek Negeri, starting from 10.30am to 1pm, where his remains will be lying in state.
"Members of the public are required to come with proper attire and in black," he told a news conference here.
He said Adenan's remains have been taken to his private residence in Santubong Wednesday afternoon.
At 10am today (Thursday), Adenan's remains will be taken to the state mosque in Petra Jaya for the lying-in-state.
Choking back tears, Abang Johari described Adenan, as a personal friend since their younger days.
"His death is unexpected," he said.
"When we met him yesterday afternoon, he was cracking jokes and in jovial mood," Abang Johari related to reporters, indicating that fellow Deputy Chief Minister Datuk Douglas Uggah Embas was also present at the meeting with Adenan.
Abang Johari added that Adenan had been a dedicated man who believed in service; his death is a great loss to Sarawak and the country.
"Since becoming chief minister in 2014, he had brought the status of Sarawak to a new level.
"One of the things he had tried to achieve was to reclaim the state's rights from the federal government, which he had done well as he is a good friend of the prime minister," he said.
Asked on who would be taking over from Adenan as chief minister, Abang Johari said it will be decided later after the seven-day mourning period is over.
"Right now, we have to give respects to the chief minister and his family," said Abang Johari, who is also PBB deputy president.