The United Nations is immune from a lawsuit seeking compensation for victims of a deadly cholera outbreak in Haiti, a US judge said in dismissing a case that government lawyers said could open international body to an onslaught of litigation.

US district Judge J. Paul Oetken noted on Friday that the UN's charter provides broad legal immunity and that the international body has not waived it.

The suit refers to an outbreak that has killed more than 8,000 people and sickened more than 700,000 since human waste was dumped into Haiti's principal river in October 2010.

Scientific studies have shown that cholera was likely introduced in Haiti by UN peacekeepers from Nepal, where the disease is endemic.

The lawsuit, filed by human rights groups and others, argued the UN had not screened the peacekeepers for the disease and was responsible for poor sanitation and waste disposal practices that spread it.

Seeking unspecified damages, the suit said the UN sacrificed its immunity by not giving victims any avenue for compensation.

"Where such an express waiver is absent, the UN and [its operation in Haiti] are immune from suit," Oetken wrote.

Lawyer Beatrice Lindstrom said the rights groups plan to appeal the ruling. Two other similar federal suits also are ongoing.

"The court's decision implies that the UN can operate with impunity," Lindstrom said in a statement. "We don't think that is the law."

'UN needed immunity'

US federal prosecutors argued against the suit at a hearing last fall. They said that the UN needed immunity to complete its global mission, and letting the case continue would subject the international body to many more lawsuits from around the world.

A spokesman for the US attorney's office in Manhattan declined to comment on the court's decision. The US government was not named in the suit, but federal prosecutors said they got involved because the US is the UN's host nation.

The UN has repeatedly declined to comment on the lawsuit but has said it is working with Haiti's government to eradicate cholera.

In December 2012, Secretary-General Ban Ki-moon announced a $2.27bn initiative to help eradicate cholera in the impoverished Caribbean nation.

In November, the head of Doctors Without Borders' Haiti mission said the country's health system still lacks the capacity to treat cholera patients adequately.

Source: Al Jazeera and agencies