Haitians paused Tuesday to mourn the 200,000 people killed six years ago in a devastating earthquake that left the country with wounds that have yet to heal.

Almost 60,000 people are still homeless and living in camps, and the common struggle to rebuild has done nothing to close Haiti's deep political divisions.

"Six years on and we still don't know the exact number of our dead, nor all their names," complained the feminist collectives Kay Fanm and SOFA.

"Six years in which families have struggled to grieve because they still don't know the fate of those who have not been seen since that tragic day."

President Michel Martelly, who will be replaced next month if Haiti manages to hold the second round of a delayed election, tried to brush off controversy.

"It's easy to criticize, but I ask that everyone look to themselves and ask themselves what they can do to help build the new Haiti," he told reporters.

On Tuesday, Martelly joined Prime Minister Evans Paul to lay a wreath at a memorial just outside the capital over a mass grave holding tens of thousands.

Flags flew at half-staff across Haiti, the western half of the Caribbean island of Hispaniola, bleakly notorious as the poorest country in the Americas.

"We're here to pay respect to all those we've lost," Martelly said, pushing his theme that it is time for Haiti to work together.

"But especially we are here to reflect on the fact that we share responsibility for what happened," he argued.

"We did not build well, we were not well-prepared, and people were not secure enough to avoid this catastrophe."

On January 12, 2010, shortly before 5:00 pm, a seven point quake destroyed more than 300,000 buildings in downtown Port-au-Price and across southwest Haiti.

Aside from the dead trapped in the tangled webs of steel and cement formed by pancaked concrete homes, more than a million-and-a-half were left homeless.

The scale of the horror triggered international sympathy and unprecedented pledges of aid, much of which was swallowed up in emergency relief.

Longer term reconstruction has been hampered by political chaos and by a cholera epidemic credibly blamed on poor hygiene at a UN peacekeeping unit.

Haiti's international partners now hope that a new chapter may begin after January 24, when voters will be called to cast ballots in a presidential run-off.

Martelly's favored successor Jovenel Moise emerged ahead of challenger Jude Celestin in a first round that the opposition alleges was marred by fraud.