In southern Haiti, trunks of uprooted trees still litter fields and beaches as if Hurricane Matthew blew through and left its trail of death and destruction only yesterday.

If it weren't for the blue plastic tarps that now cover damaged homes, the scene one month after the storm would be practically identical to the days following the October 4 landfall.

Among the felled coconut trees, a single plastic tarp offers little protection from the elements for Jean Robert Sima and his 92-year-old father, who rests on a mattress.

"A man I had done some work for is letting us use his house to spend the night because he is abroad, but that's only for a few days" and only at night, Sima said.

Every day, Sima and his family visit the ruins of their home which he hopes to rebuild. But with his crops ruined, he has no money to buy materials and is unable to find any help.

- 'People grow agitated' -

The southern region of Haiti, considered the country's breadbasket, was hardest-hit by the powerful storm, which packed winds of 150 miles (250 kilometers) per hour and killed 546 people, according to official figures.

Thirty miles away in Les Cayes, the capital of the southern department, a teenager was shot dead on Tuesday as a ship was unloading humanitarian aid.

"When aid is distributed, people grow agitated and belligerent," said Sima's wife Jiland.

"The Haitian officials are dishonest because they first take aid for their loved ones. You can be there with your kids and nothing else, but they still won't give you anything."

Receiving aid is a challenge for the tens of thousands of local residents in part because there have been no comprehensive surveys of how much assistance is needed due to the extent of the damaged area.

Just two miles awa, a religious group has discreetly distributed plastic tarps and tools to build temporary shelters.

"We conducted surveys in remote areas to verify who is in need," said Bertrand Enoc with the Adventist Development and Relief Agency (ADRA).

Hundreds of people have received emergency kits from a truck parked inside the police station in the small town of Roche-a-Bateaux.

"We cannot help everyone, so some people will receive nothing and could be tempted to protest in the streets," Enoc said.

The lucky families head to their damaged homes with aid packages tied to motorcycle taxis or on mules, under the jealous gaze of downtown residents.

- 'Never enough' -

"From the people's point of view it's never enough and they are right," said John Ging, director of operations for the UN Office for the Coordination of Humanitarian Affairs (OCHA).

"But if we take a step back and we see the number that has been reached, the quality of the assistance, it is a good operation. It does need of course to speed up but it also needs to be done properly," said Ging, who was in southern Haiti on Friday.

The issue of security is paramount for agencies distributing aid.

"It's a legitimate frustration but of course expressing their frustration in ways like looting the aid, creating security problems at aid distribution, that's not going to help anybody," Ging said.

The World Food Program has distributed food assistance to nearly 400,000 people one month after Hurricane Matthew, but the UN estimates nearly four times that number are in need.

One major problem remains insufficient funding: the World Food Program needs $58 million to carry out its work in Haiti and organize the difficult logistics to reach remote areas. So far it has only $18 million.

Such underfunding is exasperating for Ging, who complains of rich nations shirking their commitments.

"If the G7 and the G20 (groups of nations) would step up to their state of commitment of 0.7 percent of GNI for overseas development aid, we would have another $158 billion available for humanitarian and development assistance," he said.