The contents of 56 safe deposit boxes were taken during the raid in London's jewellery district over Easter weekend.
Twelve addresses in the London and Kent area were raided by about 200 police officers on Tuesday morning.
Nine men were arrested and a number of high-value items were recovered, police said. Searches of the houses are ongoing.
Scotland Yard first arrested seven men, aged between 48 and 76. They later arrested a 58-year-old man and a 43-year-old, bringing the total number of men arrested to nine.
Police have also appealed for information on a white Transit van seen in the area at the time of the raid.
The van, with a registration of DU53 VNG, was caught twice on CCTV during the Easter heist.
During a press conference, the Met said it felt officers had been portrayed as the Keystone Kops, while a relative of a victim said finding some of the haul could actually make things worse for those affected, as it could delay insurance pay-outs.
Thieves used heavy cutting equipment to break into a vault at Hatton Garden Safe Deposit Ltd, where they ransacked about 70 boxes.
The men were arrested in Enfield, east London and Dartford.
Police said bags containing a significant amount of high-value property were recovered at one of the addresses and they were confident some were items stolen during the burglary.
Head of the Met's Flying Squad, Det Supt Craig Turner, urged victims of the crime to "stay patient", adding police officers would be in contact with them in order "to restore this property back to its rightful owners".
He said the investigation had been "complex and exceptional".
In response to questions about why police did not respond to an alarm that went off at the premises during the time of the heist, Det Supt Turner, said: "We are now in a position to confirm that on this occasion our call handling system and procedures for working with the alarm monitoring companies were not followed.
"Our normal procedures would have resulted in police attending the scene and we apologise that this did not happen."
There has been no official detail of what was stolen but it is believed jewellery worth up to £200m was taken during the raid.
Cdr Peter Spindler said: "At times we have been portrayed as if we've acted like Keystone Kops.
"But I want to reassure you that in the finest traditions of Scotland Yard, these detectives have done their utmost to bring justice for the victims of this callous crime."
A relative of one of the victims said those affected were "probably worse off after this morning's raids".
"With the stolen goods vanished, there was pressure on insurance companies to settle quickly to enable holders to trade again," the relative, who did not want to be identified, said.
"But now, with a whole mess of stuff to sort out, it may drag on for months.
"If batches of the stones were mixed up, it may be impossible to reunite them with their owners."
The biggest heist in the UK was carried out at a Securitas cash depot in Tonbridge, Kent, in 2006 when robbers stole almost £53m in cash.
In 2000, police stopped an attempted £350m diamond raid from a display at London's Millennium Dome in what would have been the world's biggest-ever robbery.
Detectives hunting the gang behind the Hatton Garden safe deposit raid have arrested nine suspects.