"We are aware of the recent influx of people from Niger into some parts of (southern) Katsina State," Sani Makana, the state agriculture commissioner told AFP by phone from the state capital Katsina.
The number of of Niger nationals in northern Katsina state, which shares a land border with Nigeria, has soared in the past two months, residents said.
Makana said some were so desperate they had been forced to beg door-to-door..
"It is a pathetic sight. They just have nothing to live on and have to beg to eat," said Katsina resident, Abubakar Shehu.
"When you ask them why they came here they tell you that they were starving in Niger... and would die if they stayed," Shehu said.
According to the United Nations around 7.8 million Nigeriens are in need of food, out of the around 10 million affected by a crisis in the Sahel region.
Many Niger men in Nigeria have turned their hand to selling water in order to eke out a living.
Vendors pushing two-wheeler carts laden with 25-litre (five-gallon) jerry cans have become a common sight in Katsina city, said resident Ibrahim Salihu.
A Nigerian immigration officer, who asked to remain anonymous, said there was little his officials could do to stop the influx.
"There is very little we can do... due to the porous nature of the over 1,000 kilometre (63 mile) border stretch," he said.
In anticipation of the influx, Katsina authorities have stockpiled grains for distribution, Makana said.
Niger's transitional government at the weekend announced the launch of a food distribution operation for nearly 1.5 million people facing severe shortages.
West African ministers also met on Wednesday in the Togolese capital of Lome to discuss the crisis, an official statement said.
