Officers removed Hermes and Louis Vuitton bags as part of a trove whose value they said they could not yet estimate because of its sheer volume.
The discovery adds significantly to the peril faced by Najib, who just last week had seemed to be cruising toward an election victory before a stunning upset.
Police launched extensive searches of Najib's home and several other sites starting late Wednesday, making good on a pledge by the new government headed by 92-year-old Prime Minister Mahathir Mohamad to investigate Najib.
Officers had previously declined to comment on the searches.
But Amar Singh, head of the Malaysian police commercial crime investigation unit, on Friday confirmed the raids were linked to investigations into accusations that Najib, his family, and cronies looted billions from a state investment fund he founded.
"I can't give an estimated value of the items," Amar told reporters at the upscale Kuala Lumpur condo complex where the raids were carried out.
"We have sealed the bags but we know they contain money and we know they contain jewellery."
Members of the Royal Malaysia Police standing at the entrance of former prime minister Najib Razak's residence in Kuala Lumpur. Source: AFP
Moneybags
Singh said 72 of the bags were filled with large amounts of "various currencies, including Malaysian ringgit, US dollars, watches and jewellery".
"The amount of jewellery is rather big," he said.
Footage captured by local media showed cardboard boxes and suitcases, sealed in plastic wrapping, being loaded into a black police truck. It took five trucks to remove all of the seized items, reports said.
Just last week, 64-year-old Najib was widely expected to lead his powerful Barisan Nasional (National Front) political machine to victory, extending a more than six-decade reign that had made it one of the world's longest-serving governments.
But his coalition - accused of ballot-box stuffing and gerrymandering - was unexpectedly trounced by a diverse alliance that rallied public support against Najib's suspected corruption and increasingly repressive tactics.
The handbag discovery will add to public scorn for Najib's wife Rosmah Mansor, who has long been reviled by Malaysians for her perceived haughty demeanour and reported vast collection of designer bags, clothing and jewellery collected on jet-set overseas shopping trips.
Rosmah Mansor the wife of Malaysian Prime Minister Najib Razak pictured during the 60th National Day celebrations at Independence Square in Kuala Lumpur (2017). Source: NurPhoto
Her reputation contributed to voter perceptions of rot in a ruling establishment that had lost touch with economically struggling and middle-class Malaysians.
Mahathir had already barred Najib from leaving the country in the wake of last week's election over allegations that he oversaw the looting of billions of dollars from sovereign wealth fund 1MDB in a breathtaking and complex campaign of fraud and money-laundering stretching around the world.
The police actions have fuelled speculation in Malaysia that Najib would soon be taken into custody, but so far there has been no indication that his arrest was imminent.
Mahathir and Anwar Ibrahim, the former opposition leader who was jailed under Najib but freed on Wednesday, indicated this week that they expected charges to be filed against Najib soon.
