About one third of Kenyans are suffering in the drought
Kenya has mobilised its military, police and national youth service to distribute food, water and medicines to areas hit hardest by drought.
The government estimates that at least 10 million Kenyans - one third of the population - is in need of food aid.
At an emergency cabinet meeting, it was also decided to keep schools open through the current holidays so the food programme could continue.
Many farmers have abandoned villages in search of water and pasture for cattle.
The BBC's East Africa correspondent says drought and high global food prices, combined with last year's post-election violence has contributed to the crisis.
However, he also says that the government has come under increasing criticism for not responding to the food shortages earlier.
Government measures introduced earlier this year to allow duty-free maize imports and subsidised fertiliser have failed to ease the situation.
Meanwhile, the United Nations Food and Agricultural Organisation (FAO) said a giant herd of cattle have been driven across the border in northern Kenya into the Borena zone in Ethiopia by farmers in search of scarce pastures.
They say it is one of the largest movements of cattle in a decade.
The herd numbers more than 200,000.
"Although seasonal migration across the border is normal, this is the largest influx recorded in 10 years," a UN statement said.
"This large influx may potentially result in the spread of livestock diseases, adversely impacting the cattle export market in Ethiopia."
Tarekegn Tola, the FAO representative in Ethiopia, says food and water stocks are being depleted as Kenyans bring the cattle in.
The UN says a quarter of a million children in southern Ethiopia are already malnourished.
The drought has also hit Kenya's capacity to generate hydro-electricity, with electricity rationing introduced last week.
In January, President Mwai Kibaki said 10 million Kenyans were facing starvation.
He said this was due to drought and the effects of post-election violence, which forced thousands of farmers from their lands.