Kent Police said anything confiscated from Lee Murray would go to insurers.
The 31-year-old, originally from south London, is serving a 25-year sentence for his part in the Tonbridge depot raid, Britain's biggest cash robbery.
Murray, a Moroccan national, is behind bars in the north African country, were he fled after the raid in 2006.
A spokesman for Kent Police said: "There are ongoing proceedings by Kent Police in seizing and confiscating assets from Lee Murray in Morocco."
Last November Murray, who was jailed in June 2010, lost an appeal against his original 10-year sentence during a hearing in Rabat.
Instead his term increased to 25 years after prosecutors argued his sentence was too lenient.
The Securitas gang kidnapped depot manager Colin Dixon, his wife Lynn and their young child and held them hostage while they robbed the depot.
Heavily-armed robbers trussed up 14 terrified employees with cable ties and threatened to kill them if they disobeyed orders.
Five men were convicted of kidnap, robbery and firearms charges in 2008.
Murray's best friend and fellow cage-fighter, Paul Allen, from Chatham, in Kent, was jailed for 18 years in October 2009.
During the trial of the other gang members Murray was described as the man who organised the raid.
A cage-fighter who was jailed for his part in the £53m Securitas robbery is to have his assets in Morocco seized by police.
