Crimestoppers have offered the reward as authorites continue to look for Leon Cullen.
30 year old Cullen from Warrington remains wanted for conspiracy to supply firearms and conspiracy to supply Class A drugs, namely cocaine.
A European Arrest Warrant has also been issued.
Cullen is believed to be part of an organised crime group which saw 20 men sentenced to a total of 185 years at Liverpool Crown Court on Friday 18 January for conspiracy to supply firearms, cocaine and cannabis.
He is described as white, around 5ft 8 in height, of a slim build with short light brown hair, a tanned complexion and prominent white teeth. He also has two distinctive tattoos. Cullen has links to the whole of the north-west.