Christian aid agency World Vision is getting ready to distribute emergency aid in spite of damaged roads and infrastructure following the massive earthquake that struck Haiti on Tuesday.

Thousands are feared to have been killed in the worst earthquake to hit the Caribbean nation in 200 years.

Rescuers have been working round the clock to free survivors from the rubble since the 7.0 magnitude quake struck 10 miles south of the capital Port-au-Prince at 1653 (2153 GMT) on Tuesday.

The quake flattened buildings across the city, including the presidential palace and UN headquarters. The UN said large numbers of its personnel remained unaccounted for, among them the head of its mission in Haiti, Hedi Annabi.

World Vision staff are due to assess damage today and start distributing basic necessities like first aid kits, soap, blankets, clothes and bottled water to the thousands of survivors.

Magalie Boyer, of World Vision Haiti, said there was “extensive damage” in the city and that people had taken to sleeping out on the streets because they did not feel safe in their houses.

World Vision is mobilising staff from less affected regions to help with the relief effort. World Vision aid worker Crystal Penner was in the central plateau region of Haiti when the quake hit. She said that although relief goods were already prepositioned around the country, it would be a challenge to bring them swiftly to the people in need.

Edward Brown, World Vision’s relief director in the US, said: "We would be very concerned about a quake of this magnitude anywhere in the world, but it is especially devastating in Haiti, where people are acutely vulnerable because of poor infrastructure and extreme poverty."

Frank Williams of World Vision Haiti told CNN that people in the city were left very scared by the quake and several aftershocks.

“It’s a pretty disconcerting situation. You’ve got pretty much people screaming all around the city of Port-au-Prince,” he said. “Most people not holding it together emotionally.”

The building in which World Vision Haiti’s offices are housed shook for around 35 seconds but remained standing, although staff had been unable to leave for several hours as debris from other buildings had blocked off the surrounding streets. Mr Williams said none of his staff had been injured.