Use of heroin has shot up across the region recently
Arrests for heroin possession, and seizure of the drug, rose by more than 80% in the last year, according to South Wales Police.
There was also a rise in the number of deaths from use of Class A drugs.
That will bring organised crime and gun culture usually associated with drugs, he said.
The region already has the cheapest heroin and cocaine in the UK, police say.
In a frank admission, Sir Anthony said intelligence had put the force on alert for a big influx of drug-related crime.
During a 1030 BST press conference at police headquarters in Bridgend, he unveiled a new strategy in the fight.
That so far means the appointment of Assistant Chief Constable Dave Francis to a new taskforce charged with drawing up an action plan.
There was also a call for help from drug agencies and the public.
He indicated "a whole new ball game" had to be played to combat the anticipated menace.
'Communities destroyed'
"What our intelligence gathering shows us over the last couple of months is that we are now facing similar problems [to elsewhere] and I think the public has a right to know," Sir Anthony said.
"We've already seen a certain amount of leakage into Wales from Bristol, but we are holding back the tide.
"We want to hold back the level of organised crime in south Wales and not see the violence happening here that has been seen elsewhere.
"I am extremely concerned about the amount of heroin, crack and cocaine coming into the country."
In March, families of users in the Valleys complained more cash was needed to stop their children dying while waiting for detox programmes.
Earlier, Sir Anthony suggested warned the region would become like New York City, before mayor Rudoplh Giuliani ordered a zero-tolerance crackdown.
'Gun culture'
"Heroin and cocaine use is already ripping our communities apart," he said.
"The scale of violence, volume of crime and the gun culture that goes with the organised crime territory could destroy them completely."
He said Wales was "there for the taking" by drug dealers.
The epidemic was spreading everywhere and the country could not bury its head in the sand, he warned.
The South Wales chief constable's hardline agenda could be seen to contrast with the tactics recommended by his counterparts in other Welsh forces.
In October, former Gwent Police Chief Constable Francis Wilkinson recommended legalising heroin to tackle street crime.
In December, North Wales Police Chief Constable Richard Brunstrom said a Royal Commission should examine legalisation of all drugs.