The number of children abducted and taken abroad by an estranged parent has risen by 88% in just under a decade, according to new government figures.
About 270 new cases were reported in 2003-4, while this year so far there have been more than 500 new cases, data from the Foreign Office (FCO) showed.
It is illegal for a parent to take a child overseas without permission from others with parental responsibility.
But 24% of Britons are unaware it is a crime, separate FCO research suggested.
The FCO has launched a campaign to highlight the issue.
"We know that before or during school holidays is one of the most common times for a child to be abducted," said Daisy Organ, the head of the FCO's child abduction section.'Think twice'
"We hope that this campaign will help inform and educate the UK public and encourage parents thinking of abducting their child to think twice before they cause significant distress to themselves and their family."
Alison Shalaby, chief executive of the charity Reunite, said: "It is important to remember that parental child abduction is not faith or country specific - 71% of the UK public thought that parents most commonly abduct their children to the Middle East, India and Pakistan but it can happen to anyone, from any background."
She said children had been abducted by a parent and taken to France, Australia, Thailand and many other countries, some of which had few processes in place for returning such children.
Between 2001 and 2011 there was a 206% increase in the number of children taken to a country which had not ratified the Hague Convention on child abduction, an international agreement between certain countries which aims to ensure the return of a child who has been abducted by a parent.
According to the FCO research, 74% of people thought fathers were most likely to abduct their children but statistics from Reunite International suggest 70% of their cases concern mothers taking the child.