Sex offenders and paedophiles are travelling to the world’s conflict zones to prey on vulnerable children, the National Crime Agency has warned.

Robert Jones, deputy director of the NCA’s child exploitation and online protection command, said offenders were exploiting the chaos of war and areas hit by natural disaster. He urged the aid sector to help make it as difficult as possible for individuals to commit crimes abroad.

Jones said: “The challenge of impoverished children being exploited and people going to conflict zones to identify and exploit vulnerability needs a global effort to tackle it. People will identify vulnerability in a conflict zone, or an area hit by natural disaster. It’s a trait of their character that they will almost sniff that vulnerability out and then prey on it.” His comments coincide with calls for the UN to demonstrate leadership on the issue.

On Friday a UK delegation travelled to New York to encourage support among UN security council members for the organisation, which has 100,000 uniformed peacekeeping personnel, to implement robust child safeguarding measures.

Academics from the University of Reading and the London-based charity Keeping Children Safe have developed a toolkit they say will close a “gap in the UN’s protection agenda” and help safeguard minors from potential exploitation and abuse.

Allegations of sexual abuse by UN peacekeepers have emerged in a number of countries in recent years, including the Central African Republic, Haiti and South Sudan, prompting concern over the organisation’s failure to hold those responsible to account.

The scandal has also affected the charity sector, with Oxfam accused of concealing the findings of an inquiry into claims that staff used sex workers, possibly underage girls, while delivering aid in Haiti in 2011.

The toolkit assesses safeguarding measures, trains staff and makes sure UN staff are aware of the laws in relevant countries.

Professor Rosa Freedman, from the School of Law at the University of Reading, said: “Children in parts of the world affected by war, conflict or natural disasters are among the most vulnerable to abuse. We look to the UN, as the global leader, to protect the most vulnerable, and to make safeguarding of children a critical and visible element of all its work. We hope that world leaders will champion our call by tabling a UN resolution on child safeguarding.”

Sarah Blakemore, director of Keeping Children Safe, added: “World leaders must take swift and concerted action to ensure organisations protect children from abuse and do all they can to ensure that the perpetrators of these horrific acts are brought to justice.”

The NCA’s Jones welcomed the attempts to tighten protective measures in peacekeeping and humanitarian situations, and said that creating a “very strong misconduct regime in the aid sector” would help.

He said: “We can prevent activity by making sure the actors involved have been through a vetting process. If they are going into a position of trust, then making sure references have been taken.

“The crucial thing is that, if inappropriate behaviour has been detected, [staff] don’t just resign, move or reinvent themselves and travel to the next conflict to do what they have done before.”

Jones added that any UK nationals caught abusing children in conflict zones or humanitarian emergencies would face legislation that allows them to be charged in Britain for sex offences committed overseas. The law was used in 2016 to prosecute Richard Huckle, a photographer from Kent, who posed as an English teacher and philanthropist in poor Christian communities in Malaysia to abuse up to 200 babies and children.