Gloria Amparo lives every minute of her life with the knowledge that the gangsters who hold Colombia’s Pacific coastal region in thrall could kill her because she helps the women they have raped, the mothers whose sons they have chopped up, or the families they have displaced and tormented.

But it is not death that Amparo fears, despite the notorious brutality of these gangs, who traffic drugs and run extortion rackets in the port city of Buenaventura, governing every aspect of the population’s lives.

“[My biggest fear] is to die. Because then we won’t be able to serve. That’s it for me. There is so much to do,” says the 51-year-old member of Butterflies, or Mariposas, a women’s rights network that was awarded the annual Nansen Refugee award by the UN high commissioner for refugees (UNHCR) last week.

Amparo’s fellow activist, Mery Medina, agrees. “We are all afraid, but also [our fear is] if they don’t try to kill us, they might use other methods to stop us continuing this work,” she says, citing the possibility of threats and intimidation.

Since it was established in 2010, Butterflies has helped an estimated 1,000 women and their families. The 120 volunteers move through the city’s most dangerous neighbourhoods on foot, by bus or on bicycles. They help women access medical care and encourage them to report crimes, often working with displaced people.

After decades of conflict between the leftist Farc rebels and the government, and also between illegal gangs spawned by the wider fighting and drug trafficking, Colombia has the highest number of internally displaced people due to conflict after Syria. Women make up more than half of the at least 5.7 million people that the government estimates have been displaced.

Amparo, Medina and Maritza Asprilla Cruz came to Europe to accept the Nansen award in Geneva. They describe Buenaventura as a bereft city, where the absence of state services and amenities directly contributes to the endemic, terrifying violence. Since 1995, 147,000 people have been displaced in the city, according to UNHCR.

“We are in a forgotten land,” says Amparo, a long-time activist who had to flee the capital Bogotá in 1993 because of threats on her life. She has also been threatened in Buenaventura. “The Colombian Pacific [region] lacks investment. We need this social investment to allow us to develop, and to have autonomy.”

The women hope the Nansen award will strengthen their position back home, but they are pragmatic enough to know that it will not eradicate the risks that govern their daily lives. “What we do know now is that we are no longer on our own,” Amparo says.

Human Rights Watch (HRW) said in March that violence last year drove more than 19,000 people from their homes in Buenaventura, more than in any other municipality in Colombia. It said paramilitary successor groups had abducted and disappeared “scores and possibly hundreds” of people in the city.

Colombian navy special forces on patrol in Buenaventura. Photograph: Fernando Vergara/AP

Gangs slaughter victims in so-called “chop-up houses”, sometimes dismembering them while they are alive before throwing the bodies into the sea. HRW quoted residents as saying they had heard people scream and plead for mercy. In the rural areas around the city, the Farc guerrillas are also still active.

HRW said prosecutors had opened more than 2,000 investigations into “disappearances” and forced displacements over the past two decades but none had led to a conviction.

Medina says economic deprivation contributed to the violence. “Peace will come if we have social investment. We lack jobs, good education, medical services. We do not have spaces where children can enjoy their childhoods … 80% of the population live in absolute poverty. All this comes together to create violence.”

Social investment would be a game-changer for the young men who join, or are forced to join, the gangs, Amparo says. “If a youth has alternatives … that would satisfy the basic necessities of a family, then he would not easily go to these groups.”

In a September report (pdf), the Norwegian Refugee Council also shone a spotlight on the climate of terror in Buenaventura. “Due to the sexual assault and abuse of women and girls in their homes or in public places, such as stores and on the way to school, women live in a state of fear. Mothers are afraid to let their daughters out alone. In Buenaventura, there is a sustained collective fear that undermines the community’s social welfare,” it said.

Asprilla Cruz, who works as a waitress in addition to volunteering for the Butterflies, remembered the plight of a mother whose 14-year-old son was abducted a year ago. She still does not know where he is. The mother reported the case to the police but nothing was done.

“It is very sad for a mother to hear that her child has been killed and chopped up and to be crying and not know where he is … She keeps hoping. She is just there, carrying her cross,” Cruz says.

With the $100,000 (£62,500) prize money from the Nansen award, the Butterflies plan to open a safe house for victims of violence. “This is going to be the first decoration in our safe house,” says Medina, pulling the Nansen award – a gold medal – from a bag. “We never lose hope,” she adds. “This sustains and strengthens us. Peace will come if we have social investment.”