Those warnings have been echoed privately by at least three impoverished states who say they are being shortchanged.
In his first full-year budget, approved by parliament on May 7, Modi halved funding for a scheme that gives millions of poor children free food and drastically cut allocations to make clean water available in rural areas.
On the other hand, funding for roads and bridges more than doubled and is now higher than the sum allocated to education.
The cuts to nutrition and water stand out because of the precarious condition of India's poor. Four of 10 stunted children in the world are Indian, more than sub-Saharan Africa.
In 2013, the country recorded 50,000 maternal deaths. About 1.5 million children die each year before the age of five.
Modi's first year in office has seen a string of successes, including forging closer ties with major trading powers, boosting foreign investment and cutting red tape.
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His approval ratings remain high, although he faces growing headwinds in the countryside, where bad rains and low crop prices have affected the 70 percent of the people that live there. The fear is that the spending squeeze will hit when the most vulnerable need more help.
"Increasing signs of rural distress in India make Modi's cuts politically risky," said Milan Vaishnav of the Carnegie Endowment for International Peace.
Modi's gamble is that infrastructure investment will generate dividends for the poor in time for the next general election by increasing the economy's capacity to grow through better roads, ports and railways.
At the same time as taking away central funding, Modi has increased the share of taxes given to states to 42 percent from 32 percent, money that, if well spent, can cover the shortfall from the spending cuts.
The policy shift is championed by economists in a new body called Niti Aayog, or policy commission, Modi's replacement for the Soviet-style Planning Commission set up by post-independence leader Jawaharlal Nehru.
It is headed by Columbia University's Arvind Panagariya, who advocates fiscal stimulus to invest in infrastructure and restore growth, and rely on the growth to later finance health and other social spending.
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One senior government official aware of the strategy said his main priority this year was to find ways to efficiently spend the ramped-up rail and road budgets.
"This has an element of risk because it is not clear how effectively this stimulus can actually be delivered on the ground due to leakage, weak capacity, and so on," Vaishnav said.
Junior Finance Minister Jayant Sinha said the emphasis was on the supply side so the rural economy grows without overheating, but denied programs were being cut.
He pointed to increased funding for a rural work scheme that was a flagship of the last, left-leaning government.