Kidnapping and criminal association charges against 10 US Christians who tried to transport Haitian children out of the country to an orphanage have been dropped.

However, the leader of the group of volunteers, Laura Silsby, still faces a charge of arranging irregular travel and will stand trial in Haiti, Judge Bernard Saint-Vil said Monday.

Silsby, who remains jailed in the Caribbean country, could face up to three years in prison if convicted.

The latest announcement comes a week after the Haitian judge corrected earlier reports that indicated the charges against the group were dismissed. While a spokesman for Idaho Senator Jim Risch said the senator was told on April 15 by the State Department that nine of the volunteers no longer faced any charges, Judge Saint-Vil said last week he had yet to make a decision at that time.

Most of the 10 Americans belong to two Baptist churches in Idaho.

The team travelled to Haiti in January after a massive earthquake devastated capital Port-au-Prince. Plans to build an orphanage in the Dominican Republic for Haitian children had already been in place and the disaster prompted them to accelerate their plans.

They attempted to take 33 Haitian children to the orphanage they were setting up in the neighbouring country but were arrested on January 29 and subsequently charged with kidnapping a minor and criminal association.

The volunteers said they simply wanted to help the children who lost their parents after the massive earthquake. But complications arose when they were found without all the proper paperwork and it emerged that many of the children had at least one living parent.

Last month, Judge Saint-Vil brought additional charges of "organising irregular travel" against Silsby after discovering an earlier attempt to take the children out of the country. The team tried to take 40 children to the Dominican Republic on January 26.

Silsby will stand trial along with Jean Sainvil, a Haitian-born pastor from Atlanta who also helped organize the venture, according to The Associated Press. The trial could begin as early as this week.

Nine of the volunteers were allowed to return to their homes in the US in February and March.