Haitians are to fast and take part in prayer vigils to mark one month since a huge earthquake struck on January 12, reports the BBC.

As the Haiti government revised the death toll from last month's earthquake to at least 217,000, Friday has been declared a day of mourning.

According to the results of a new World Vision survey, 92 per cent of survivors in devastated capital Port-au-Prince have lost a loved one.

The survey asked the experiences of 150 people across three sites in Port-au-Prince where it is aiding survivors.

Of those surveyed, 49 per cent said they had lost an extended family member, while 43 per cent had lost a member of their immediate family.

The Christian aid agency said the quake response needed to deal with more than just the material needs of survivors and help them come to terms with their grief.

World Vision’s emergency specialist Joanna Trevor said Haiti was a nation in mourning.

She said: "The effects of trauma on an individual can be devastating in the long term but when it’s on the scale that we’re seeing in Haiti, the country’s recovery is under threat.

“The focus now has to be on helping men, women and children to begin to cope with their loss.

“Simple things done now can make all the difference.

“Giving children and families the opportunity to grieve, to establish a routine, and to access the basics – food, water, shelter – are all critical steps in this process."

Billions of dollars worth of aid have been committed to the ongoing response. Christian aid agency Tearfund warned survivors still have very little in the way of basic necessities.

Tearfund partner, the Federation of Protestant Schools of Haiti, is launching the SOS Project to help meet the basic needs of 3,000, including 1,800 children.