On BBC One's Crimewatch, Det Supt Craig Turner, head of the Flying Squad, appealed for witnesses to the burglary, which took place over Easter.
New CCTV images of the thieves entering and leaving Hatton Garden Safe Deposit Ltd have been released.
The contents of 56 safe deposit boxes were taken in the raid.
Items were removed from the premises in wheelie bins and bags during the raid in Central London.
No arrests have yet been made.
In total, 72 boxes were opened. Five were vacant and 11 were due to be opened by the company following the non-payment of fees, police said.
Launching the fresh appeal, Scotland Yard released 14 images of six suspects entering and leaving the building over the Easter weekend.
The thieves first went into the building after 21:00 BST on Thursday, 2 April and left shortly after 08:00 BST on Good Friday, 3 April, police said.
They returned to the scene soon after 22:00 BST on Saturday, 4 April and were recorded on CCTV leaving the premises at around 06:40 BST on Easter Sunday, 5 April.
Scotland Yard said that on both days male "A" makes his way to the side exit of Hatton Garden Safety Deposit Ltd, where he let the other gang members into the building.
A picture of the Hilti DD350 drill used by the gang to bore through a concrete wall to access the vault, has also been released.
The hole measured 50cm (20in) deep, 25cm (10in) high, 45cm (18in) wide and sits 89cm (35in) above the floor.
Police have also released a graphic showing the break-in.
The Met are currently reviewing how they responded to the raid after it emerged an intruder alarm had gone off at the scene of the crime but it decided a response was not required.
Det Supt Craig Turner added:  "We are keen to hear from wives or partners of anyone who has specialist knowledge or skills that use this sort of equipment.
"Were they away during the Easter Bank Holiday weekend or have they been acting oddly since the burglary was carried out?"
A £20,000 reward has been offered for information leading to the arrest and conviction of the gang responsible for the Hatton Garden heist.