The poll conducted by Today's Chanakya, the only pollster that accurately predicted the scale of Modi's election victory in May, showed almost half of the respondents felt the Hindu nationalist leader could have taken more stringent steps to curb inflation.
Modi rose to power with promises of reviving India's flagging economy and reducing prices of essential commodities, but consumer price inflation touched a two-month high of nearly 8 percent in July while food price inflation neared double digits.
More than two-thirds of those polled said the government's efforts to tackle price rise have remained unchanged or weakened over the last three months, the survey results released in two parts over late Tuesday and Wednesday showed.
Though the Indian economy grew 5.7 percent in the April-June quarter and recorded its strongest growth in 2-1/2 years, analysts say there is little hard evidence to indicate a sustained rebound.
Ratings agency Moody's on Wednesday said any upgrade to India's sovereign rating is limited by the country's fiscal deficit and inflation outlook.
While 41 percent of the respondents said the economy is back on track, 34 percent said it is still not out of the woods.
Still, echoing the sentiment of several other recent opinion polls, a large majority of respondents - 66 percent - said they were satisfied with the new government's performance so far.
On the issue of corruption, that cost Modi's predecessors dearly in the national elections, 54 percent surveyed expressed confidence the current government can effectively curb graft that plagues Asia's third-largest economy.
Today's Chanakya, part of a family-run research firm started two decades ago in New Delhi, interviewed 6,280 people across 14 Indian cities between Aug. 26 and Aug. 31 for the poll.