More than two years after a catastrophic earthquake devastated Haiti's capital, authorities on Wednesday began rebuilding the presidential palace with the help of actor Sean Penn.

President Michel Martelly and members of his government launched the reconstruction project at the ruins of the palace, which was destroyed in the January 2010 quake, which killed 250,000 people.

"The reconstruction of public buildings will henceforth commence. We must start with the national palace because it is a symbol," Martelly said.

Martelly said it would take three months just to demolish what is left of the building, the first step of the reconstruction project.

"The cost of the demolition will be kindly assumed by the humanitarian organization of actor Sean Penn, which has been working in Haiti since the 2010 earthquake," said presidential spokesman Lucien Jura.

Martelly vowed to help Haitians left homeless by the quake to move out of tents and makeshift structures, and to improve living conditions in the country, which even before the quake was the poorest in the Americas.

"Now, I am undertaking the rebuilding of the national palace for the people of Haiti," he said.

More than two years after the quake, about 400,000 people are still living in camps for the displaced in Port-au-Prince and other Haitian cities, according to the International Organization for Migration.