When DEA agents Javier Pena and Steve Murphy set out to help bring down Pablo Escobar, the head of the Medellin drug cartel had essentially declared war on his own country.

The king of cocaine was more than just South America's biggest drug smuggler; responsible for supplying 80 per cent of the market in the United States.

Escobar was the first "narco-terrorist" whose ruthlessness led to the deaths of three Colombian presidential candidates, politicians, hundreds of judges, more than 1000 police officers, an unknown number of rival dealers or enemies, as well as countless innocent people caught in the crossfire.

"When we were in Colombia, they told us 'hey, this isn't just our problem. It's the rest of the world too'," Pena told the Herald.

"They were right. The consumption of drugs affects everyone."

In the late 1980s and early 1990s, Pena and Murphy were the lead investigators working with an elite Colombian taskforce in the largest, multi-jurisdiction, high-profile investigation of its time.

The result was the demise of Escobar - worth an estimated $30 billion at the height of his power - and the first time an entire international drug cartel had been completely dismantled.

The actions of Pena and Murphy inspired the hit Netflix drama Narcos; perhaps the reason why the letters DEA - the Drug Enforcement Administration - are familiar in this part of the world.

The DEA also recently successfully prosecuted Joaquin "El Chapo" Guzman, one of the cartel leaders who followed in the footsteps of Escobar.

Likely to receive a life sentence on drug trafficking convictions, "El Chapo" was the leader of the Mexican cartel Sinaloa as the organised crime group rose to power globally.

While the DEA and murderous drug cartels seem like something from a Hollywood script, both have now reached the shores of New Zealand.

Sinaloa and rival cartel Jalisco, or CJNG, are behind an upswing in large shipments of methamphetamine and cocaine smuggled into New Zealand and Australia, the Herald revealed this week.

"If you were to ask any significant trafficker what is the best market for meth and coke in the world, they would say Australia and New Zealand," said Merkel, who is based in Canberra as the DEA attache for the Pacific region.

• READ MORE: Inside NZ's meth crisis

"The same people that are pumping drugs out to the United States are the same ones that are pumping out drugs here. If they seen potential to make more money, they're going to do it."

The DEA and New Zealand police have worked together for years but will become much closer, as the DEA opens offices in Auckland and Wellington.

Steve Murphy and Javier Pena are not surprised the cartels have taken notice of New Zealand's lucrative drug market, or the response of the DEA to also set up shop.

"I think having a fulltime office there, with one of our trusted allies, a Five Eyes partner, is fantastic," said Murphy.

Pena: "The goal of all these traffickers is to make money and they do not care where. They're going to hit every market they can."

Pena and Murphy were aware methamphetamine was a problem in New Zealand, but not the full extent as reported in the Herald's Fighting the Demon documentary released this week.

A kilogram of methamphetamine might fetch $1000 in Mexico and be worth $5000 when smuggled into the United States. The same kilogram is worth $200,000 in New Zealand.

"I was surprised by the prices [in New Zealand]," said Pena. "When I started out [with the DEA] in the mid-1980s in Austin, Texas, methamphetamine was one of the first drugs I investigated. It's easy to make, easy to smuggle, and I'm well aware of how powerful the addiction is."

The pair of special agents, now retired, are visiting Wellington in July as part of their international speaking tour about Escobar, the Cali Cartels and the Mexican drug war.

They don't tire of sharing anecdotes and insight about their world famous investigations and try to "take the audience on an adventure" with exclusive photographs and videos.

"It's a dark subject, so we try to lighten it up and have a few laughs. But it's history lesson too, about the true story of Pablo Escobar."

However, both agree the War on Drugs has failed to stop addiction around the world.

"We, as a world, cannot arrest our way out of this drug problem. But at the same time, we have to have law enforcement to protect us," says Murphy.

"We're big advocates of education at the earliest possible age."

• Capturing Pablo An evening with DEA agents Steve Murphy and Javier is in Wellington on July 17.