The World Food Programme has started its first systematic food distribution system for Haiti since the earthquake, with 16 sites set up in the capital where only women can collect food.

Food distribution since the quake on 12 January has often been marked by poor coordination, gaps in coverage, and desperate, unruly lines of needy people in which young men at times have shoved aside the women and the weak and taken their food.

The UN agency said in a statement that the fixed sites established across Port-au-Prince by it and other aid groups would ensure a regular flow of food and other humanitarian assistance to all those who needed it.

Haitians have now started receiving coupons entitling each family to 55lbs of rice. The first distributions began yesterday, with only women allowed in to collect rations. The World Food Programme said it would work with other aid groups and local authorities to make sure men in need were not excluded. The agency aims to reach more than two million people in the next two weeks. So far, it has dealt with about 600,000 people, supplying more than 16 million meals.

The organisation said the collapse of Haiti's infrastructure, losses in the aid community in Haiti at the time of the quake, security concerns and the huge scale of need have hampered their response. Executive director Josette Sheeran said the emergency was "the most complex challenge we have ever confronted".

Few tents have been supplied to the quake's survivors; rubble remains and signs begging for help in English – not Haitian Creole – dot nearly every street corner in Port-au-Prince. It could take weeks to get the 200,000 tents needed for Haiti's homeless, said Marie-Laurence Jocelyn Lassegue, the culture and communications minister. Haiti now has fewer than 5,000 donated tents and coordinating the aid operation remains a problem.

Reconstruction, resettlement and land titles are all priorities of the government of President Rene Preval – but so far in name only. The government has been nearly paralysed by the quake – its own infrastructure, including the National Palace, was destroyed – and so far it has been limited to appeals for foreign aid and meetings with foreign donors that have yet to produce detailed plans for the emergencies it confronts.

Its first priority is moving people from areas prone to more quakes and landslides into tent cities that have sanitation and security but have yet to be built. Preval held dozens of meetings with potential outside contractors to discuss debris removal, sanitation and other long-term needs.

Albert Ramdin, assistant secretary of the Organisation of American States, has offered help in creating a new Haitian land registry – a process that could take months if not years because countless government records were destroyed in the quake. Haitians ardently defend their property rights. If a family has occupied land for more than 10 years, they gain ownership rights even without a deed. For some families, small homes have been passed down through generations. Few Haitians have insurance, and the loss of what few assets they have has crippled countless families.

Many have tired of living in tents improvised from tarps, sheets and bedspreads, opting to rebuild their homes rather than find new plots. Lassegue said such rebuilding won't be tolerated – and the government wants to develop and implement a comprehensive reconstruction plan that might feature building codes, an anomaly in this impoverished nation.

"We've been sleeping outside but the rains will come soon," said Merilus Lovis (27), taking wooden planks and erecting them for walls inside the foundation of his former home, where his wife and daughter died. "I'm scared of the floods on this hillside but I don't think that God would let such bad things happen twice."

Thousands of others have swarmed to improvised tent camps, where Elisabeth Byrs, an official of the UN's humanitarian coordination office, said there was a "major concern" about sanitation. About 200,000 people are in need of post-surgery follow-up treatment and an unknown number have untreated injuries, she said.