Some adopted children have already arrived in the Netherlands
The US says it will temporarily allow orphaned Haitian children into the US, following last week's earthquake.
Homeland Security Secretary Janet Napolitano said the move would allow children eligible for adoption in the US "to receive the care they need".
Other nations said they were speeding up the process to allow Haitian children to join adoptive families.
Dutch adoption agencies sent a plane to pick up some 100 Haitian children who are being adopted by Dutch families.
A number of Haitian children had adoptions pending before last Tuesday's devastating earthquake.
But there are fears that in many cases vital paperwork will have been lost because orphanages were among the many buildings wrecked or damaged by the quake.
Children's advocacy groups have warned against starting new adoption processes in the midst of an emergency.
"We are committed to doing everything we can to help reunite families in Haiti during this very difficult time," Ms Napolitano said in a statement.
"While we remain focused on family reunification in Haiti, authorising the use of humanitarian parole for orphans who are eligible for adoption in the United States will alow them to receive the care they need here."
Ms Napolitano did not say how many Haitian children might be involved.
US Secretary of State Hillary Clinton earlier told CNN she was "personally directing that we do everything we can to try to find and identify those children who are already adoptable... and to try to expedite all the paperwork... to get them to their new home".
The US authorities are encouraging US families with pending adoptions to contact them with information about their case.
Officials believe there are at least 300 cases pending, while advocacy groups say there may be some 900 adoption cases under way.
On Sunday, several Haitian children adopted by Dutch families arrived in the Netherlands.
Canadian authorities have also indicated that priority consideration in granting immigration visas would be given to pending adoption cases.
It is believed between 1,200 and 1,500 adoption cases are pending for French families, but the French government has said its priority is emergency aid rather than organising the transfer of the children.
"Adoptive families whose procedure in Haiti has been completed and whose child has a Haitian passport can rest assured that they will be brought to France as soon as possible," the French foreign ministry said.
Spain's foreign ministry said that it was "taking all possible steps so that Haitian minors who have been adopted by Spanish families can travel to Spain given the special conditions affecting Haiti," according to the AFP news agency.
The ministry said it was currently holding meeting with families which had completed adoptions.
However, some adoptive parents are pressing for more urgent action given the humanitarian situation in Haiti.
They are also concerned that many records, which will often have taken months to finalise, may have been lost amid the earthquake damage.
The Roman Catholic archdiocese in Miami, which has a sizeable Haitian community, has proposed the airlift of hundreds of Haitian children to South Florida, in an echo of the exodus from Cuba in the early 1960 of some 14,000 Cuban youngsters.
However, the Joint Council on International Children's Services, a US advocacy group, says the immediate focus should be on the safety of children in Haiti and getting emergency help to them.
"While both airlifts and new adoptions are based on valid concerns and come from an obviously loving heart, neither option is considered viable by any credible child welfare organisation," the group said.
"Bringing children into the US either by airlift or new adoption during a time of national emergency can open the door for fraud, abuse and trafficking."
Haiti has some 380,000 orphans, the UN's childrens' agency Unicef says, but that number is expected to have increased in the wake of the earthquake.