Hundreds of thousands of Haitians still living under makeshift shelters face an increased risk of disease and poor sanitation in the coming rainy season, Adventist Development and Relief Agency (ADRA) workers said.

The rains usually begin in May but could affect the region as early as March, the agency reported.

ADRA workers in Haiti said an early morning rainstorm last week soaked through bedding and clothing and collapsed cardboard shacks in some camps, giving a taste of what days of rain could bring.

"The humanitarian situation could become exponentially worse if the issue of shelter is not resolved quickly," said Frank Teeuwen, bureau chief for emergency management at ADRA International.

Between 1.1 million and 1.5 million Haitians are living without basic shelter, the United States Agency for International Development (USAID) said. Out of that number, roughly 272,000 people have already received emergency shelter support, the United Nations reported.

ADRA plans to distribute thousands of tarps and plastic sheeting and nearly 1,000 six-person tents over the next few days. The organization is also assisting a camp of more than 15,000 people on the campus of the Haiti Adventist University in near-by Carrefour.

Adventist Church leaders in Inter-America said they are also planning for the foreseeable future -- while members currently worship outside under tarps, leaders said they hope to begin repairs on the church buildings left standing.

"We want to make sure that our temples are functioning as soon as possible," said Israel Leito, president for the Adventist Church in Inter-America. "Plans must be ... in place to repair the churches that were damaged first. Then we can concentrate on rebuilding."

Church leaders said Adventist Risk Management employees have already made an initial visit to assess some of the damage to denominational properties insured before the quake hit, which will aid in reconstruction.

Inter-American church leaders said they have asked Maranatha Volunteers International, a supporting organization of the Adventist Church, to help with the recovery process. Maranatha will construct 185 churches in Haiti with their One-Day Church program, using prefabricated steel frameworks that can be assembled in about eight hours.

In addition, the Adventist Church in Puerto Rico is working with government officials and other organizations on the island to provide about 500 wooden hurricane-resistant two-bedroom homes to both church and community members. The homes can be assembled in one week, said Jose Rodriguez, president for the church in Puerto Rico.

The Adventist world church has pledged more than $2 million in aid to Haiti so far, said Filiberto Verduzco, treasurer for the church in Inter-America.

Adventist-run colleges and universities around the world have also promised additional fundraising and medical assistance, Inter-America church leaders reported.

Inter-America church leaders said they realize the promised aid is just the beginning to the recovery process.

"[Haiti] will be a long-term project, way beyond 2010," Verduzco said.

-- Reporting by Hearly Mayr, Libna Stevens, John Torres