The appointee will set up a task-force (cabina di regia) made up of officials from several ministries, sources said on Wednesday.
The decree would also simplify the procedures regarding the interventions necessary to tackle the emergency, the sources said.
Low levels of rain and snowfall this winter have exacerbated an already difficult situation after the severe drought and long series of heat waves that Italy endured last summer hit its water resources badly.
Mild winter temperatures have also brought forward the melting of snow on the mountains, which is of concern given the water is an important source of water in the spring and summer .
Environment and Energy Security Minister Gilberto Pichetto said on Friday that water rationing may become necessary in some parts of the country because of the drought.
The emergency is causing big problems for farmers.
Farmers' association Coldiretti said on Wednesday that 300,000 farms in Italy are being affected.
Scientists say that extreme weather events like heat waves, supercharged storms, flooding and droughts are becoming more frequent and more intense because of climate change caused by human greenhouse-gas emissions.
ANSA
