Emily Sanson-Rejouis' French-Haitian husband, Emmanuel Sanson-Rejouis was killed in the 7.0 magnitude quake and their New Zealand-born daughters, Kofie-Jade, five, and Zenzie, three, are missing.
Their youngest daughter Alyahna, two, was rescued after being found under her father's body. She had one broken leg and possibly a second.
Ms Sanson-Rejouis, 37, who was in Haiti working for the United Nations, contacted her sister Rachel Sanson last night.
She and her daughter were now in hospital in the Dominican Republic, the family said in a statement.
They were not sure how the pair had got there, but were relieved they were safe.
Ms Sanson-Rejouis' mother, Jennie Wilson, father Roger Sanson and her sister Rachel Sanson were travelling to Miami.
Her husband's family in Florida were trying to get to the Dominican Republic to support the mother and daughter, the family said.
The search continued for missing girls.
New Zealand has contributed $1 million to international relief efforts.
Foreign Minister Murray McCully said it was tough as Haiti's infrastructure had been so badly affected.
"You actually do feel a sense of powerlessness when you know that there's someone in extreme distress with people affected by a tragedy like this, not only because we have no capacity on the ground ourselves, but others who do have that capacity on the ground have had it flattened," he said.
"Talking to (United States Secretary of State) Hillary Clinton this morning, she made it clear that her assessment was that just about every institution in Haiti, including the United Nations and others who play a significant role there, have just about been rendered unable to function."
Mr McCully said international agencies would need to assess what could be done to help.
"New Zealand would want to be associated with that work, if there's any way in which we could be useful without getting in the way."
A New Zealand diplomat had been sent to Miami in the US in the hope they could assist in some way, but Mr McCully said it could be difficult as it appeared the airport in Haiti was closed.
"There's some doubt as to whether we can get anyone in, or indeed if it's going to be useful to do but as a precaution we'll have someone stationed in Miami able to move quickly if that becomes the right thing to do," he said.
"I've also indicated to Secretary of State Clinton that if there is some specialist areas in which New Zealand services are able to assist, we will very quickly put people in place."
The disaster prompted Mrs Clinton to postpone her visit to New Zealand in order to focus on coordinating US relief efforts.
She told reporters she planned to reschedule her visit to New Zealand -- "where we've forged close working ties with the new government over the past year and we're going to continue to deepen those as we move forward".
New Zealanders with concerns about the welfare of family in Haiti should telephone the Ministry of Foreign Affairs and Trade on 439-8000.
Unicef, Red Cross, World Vision, TEAR Fund, Oxfam and Caritas are coordinating appeals in New Zealand.
Unicef staff were on the ground in Haiti providing immediate aid, with emergency supplies and extra personnel incoming, spokesman David Youngmeyer said.
Red Cross said as many as three million people could have been affected by the earthquake, but it was not yet known how many had been killed, injured or left homeless.
Its volunteers in Haiti were assisting injured and homeless people with its emergency supplies. Additional disaster response supplies for 10,000 families, including kitchen kits, personal hygiene articles, blankets and tarpaulins, were being dispatched from Panama.
Disaster response specialists, including experts in relief coordination, health, telecommunications, water, sanitation, logistics and shelter were expected to arrive in Haiti today.
The organisation would also establish a field hospital able to treat 50 patients. Forty tonnes of medical supplies and body bags was on route from Geneva.
New Zealand Red Cross, which had put $50,000 towards the appeal, said it would immediately send people or supplies if requested.
It could only accept financial donations, as additional people and goods could create more burden for an already strained infrastructure.
World Vision had 370 staff in Haiti who were making their way to the capital Port-au-Prince to help.
The child-focused aid agency said it was the children who would be most vulnerable as thousands were already forced into modern day slavery and hundreds of thousands lacked parental care.
"We are very concerned about the protection and well-being of the children," said Amanda Rives, of World Vision's Latin America and the Caribbean regional office.
"An earthquake of this magnitude is an extremely traumatic experience for children. Many children may be injured or separated from their families. Our priority is ensuring that children's physical and emotional needs are met, both now and in the coming weeks."
TEAR Fund was supplying medical personnel and supplies, as well as emergency food, clean water, and shelter, its acting executive director Jon Horne said.
"We do have a number of staff on the ground but communication is extremely difficult. The lack of communication has also meant that more than 680 Kiwi child sponsors are anxiously awaiting news about their sponsor children," he said.
Oxfam had 200 staff and volunteers in Haiti who had launched a large, long-term response to provide public health, water, and sanitation services to those worst affected.
