Authorities are investigating Najib as part of their probe into how billions of dollars went missing from state fund 1Malaysia Development Berhad (1MDB), which was founded by the former premier.
Since his shock election loss to Mahathir Mohamad in May, Najib has been barred from leaving the country, questioned by the anti-graft agency and has had his personal and family houses searched as part of the 1MDB probe.
Amar Singh, head of the police commercial crime division, said the retail value of the items seized from six properties linked to Najib was between 900 million ringgit ($224 million) and 1.1 billion ringgit.
"This is the biggest seizure in the Malaysian history," Singh told a news conference.
He said more than 150 police officers and external experts took nearly a month to value the seized items.
Jewelry accounted for the biggest portion of the seizure - 12,000 pieces of jewelry valued at between 660 million to 880 million ringgit, Singh said. The single most expensive item was a diamond necklace worth at least 6.4 million ringgit.
Authorities also found 116.7 million ringgit in cash, slightly higher than previously disclosed. Singh said 22 central bank officials using six cash-counting machines needed three days to count the money.
Luxury handbags and watches worth millions of dollars were also seized.
Singh said police planned to take statements from Najib and his wife, Rosmah Mansor, on the ownership of the seized items.
"We should be calling them soon," he said. "We have to verify if they were gifts from people, and if so, who are the gifts from."
In an exclusive interview with Reuters last week, Najib said most of the items seized from his houses were gifts given to his wife and daughter and had nothing to do with 1MDB.
He also said the cash found at his house belonged to his political party.