South Sudan's parliament has passed a bill that relief organizations say could restrict their work as the country faces a worsening humanitarian crisis.

The Non-Governmental Organization bill, passed unanimously on Tuesday, requires international aid agencies, civic organizations and volunteer groups to have 80 percent of their staff at all professional levels be South Sudanese. Aid groups say they struggle to find qualified local staff in a country with high illiteracy rates.

The new legislation also requires each group to sign individual agreements with a government commission. South Sudan's government says the non-governmental organizations in the country need regulation.

South Sudan faces a serious humanitarian emergency, according to the U.N., on par with Syria, due to an 18-month civil war that has displaced nearly 2 million people.