People carrying knifes have been warned they face prison terms of up to four years.
The threat came as police officers across the county take part in week-long campaign targeting those taking blades out in public.
The consequences of carrying and using a knife can be devastating and potentially life-threatening
Chief Inspector Mark Baines, from Lancashire Police, said: “Too many families have been affected by knife crime with even one person being stabbed being one too many.
“The consequences of carrying and using a knife can be devastating and potentially life-threatening.
“I would appeal directly to people that if you know someone who is carrying a knife, don’t keep silent. Report it.
“The law is simple.
“It is illegal to carry a knife, even if it belongs to someone else.
“Anyone who is found carrying a knife and is intending to use it as a weapon – even in self-defence – can be arrested, go to court and receive a police record or even a prison sentence of up to four years and an unlimited fine.”
During knife amnesties in 2014 and 2016, hundreds of knifes were placed in bins at police station across the county with no questions asked.
The same offer is not on offer this week, with people being instead asked to report those who take knives out in public, though further surrenders could be considered in the future, the force said.
Officers will also be carrying out test purchases at shops to make sure knives are not being sold to children.
Police and crime commissioner, Clive Grunshaw, added: “Knives are potentially lethal weapons and I fully support Lancashire Constabulary’s bid to get them off our streets.”