By Mariam Karouny

BAGHDAD (Reuters) - Iraq will ask the United Nations to end immunity from local law for U.S. troops, the government said on Monday, as the U.S. military named five soldiers charged in a rape-murder case that has outraged Iraqis.

In an interview a week after Prime Minister Nuri al-Maliki demanded a review of foreign troops' immunity, Human Rights Minister Wigdan Michael said work on it was now under way and a request could be ready by next month to go to the U.N. Security Council, under whose mandate U.S.-led forces operate in Iraq.

"We're very serious about this," she said, adding a lack of enforcement of U.S. military law in the past had encouraged soldiers to commit crimes against Iraqi civilians.

"We formed a committee last week to prepare reports and put it before the cabinet in three weeks. After that, Maliki will present it to the Security Council. We will ask them to lift the immunity," Michael said.

"If we don't get that, then we'll ask for an effective role in the investigations that are going on. The Iraqi government must have a role."

Analysts say it is improbable the United States would ever make its troops answerable to Iraq's chaotic judicial system.

Asked to respond to Michael's remarks, White House spokesman Tony Snow dismissed that as a "hypothetical game".

But Snow said: "We also understand Prime Minister Maliki's concerns and we want to make sure he's fully informed and also that he is satisfied, regardless of what the treaty situation may be on these issues, that justice truly is being done, and that he can make that demonstration to his people as well."