Wellington, Feb 1 NZPA - Children in earthquake-battered Haiti are more vulnerable than ever to child trafficking, the head of Unicef in New Zealand is warning.

The call comes after 10 Americans were detained on Saturday for attempting to whisk 33 children out of the country without proper documentation. Some of the children may not have been orphaned by the magnitude 7.0 quake on January 12.

As many as 1.5 million children had been affected by the quake and many were now vulnerable to illegal child trafficking, Unicef NZ director Dennis McKinlay said.

"Many children will have lost or been separated from family members and present easy targets for traffickers who are known to fish in pools of vulnerability," he said.

"Child traffickers will not hesitate to pick up unaccompanied children and whisk them out of the country."

The stretched Haitian government has halted all pre-quake adoption applications, but parentless or lost children remain vulnerable to child traffickers.

In one recent instance, a Unicef child protection team came across three Western women attempting to pick up a toddler from an orphanage, while leaving the child's 10-year-old sister behind.

Unicef intervened and handed over the case to authorities.

It was essential that Haitian children were given adequate protection from traffickers, Mr McKinlay said.

"The focus right now is on protecting children in Haiti and making every effort to reunite them with their families."

Unicef and its partners were working to establish safe spaces for unaccompanied children and were supporting Haitian efforts to increase border vigilance.

The victims of child trafficking often suffered fates including sexual exploitation and child labour, with some even being intentionally maimed and forced to beg on the streets for the benefit of their handlers, Mr McKinlay said.

Human trafficking is the third largest criminal activity in the world, after armaments and drugs.