The HSBC Emerging Markets Index (EMI), a monthly indicator derived from the PMI surveys, fell to 50.3 in March, from 51.1 in February.
Private sector output contracted in three of the four largest emerging economies -- China, India and Russia -- since February.
China posted a marginal decline for the second month running, while India slipped back into contraction.
Meanwhile, Russian private sector output fell at the fastest rate since May 2009, HSBC said.
"Emerging markets are going through a rough patch. Lacklustre demand in advanced markets has so far restrained exports. Political uncertainty locally may also be to blame, with elections coming up in key economies, such as India and Indonesia, and geopolitical tensions casting a shadow in Eastern Europe," said HSBC Co-Head of Asian Economic Research, Frederic Neumann.
New business order flows eased in March, and backlogs of work continued to decline as well. Subsequently, employment growth remained weak during the month.
During March, the HSBC composite index for India, which maps both manufacturing and services, stood at 48.9, while for China it was 49.3, Brazil (51) and Russia (47.8).
An index measure of above 50 indicates expansion.
According to HSBC, hopes regarding production output look bullish as the Emerging Markets Future Output Index that tracks firms' expectations for activity in 12 months' time was still at the second highest level in the past seven months.
"Asia had a wobbly start to 2014, no doubt. But drop in PMIs seems to be stabilising amid tentative signs of export pick-up," Neumann added.