NEW DELHI (Reuters) - New HIV infections in India could rise for the first time in more than a decade because states are mismanaging a prevention program by delaying payments to health workers, the United Nations envoy for AIDS in Asia and the Pacific said.

India's efforts to fight HIV have for years centered around community-based programs run for people at high risk of contracting the virus, such as sex workers and injecting drug users. The results won praise globally - annual new infections fell consistently and, overall, were reduced by more than half between 2000 and 2011.

But Prime Minister Narendra Modi in February cut the federal AIDS budget by a fifth and asked states to fill the gap, even though their poorly-run bureaucracies were already slow in releasing funds to their AIDS prevention units.

As a result, staff salaries have been delayed for months and prevention activities have slowed down.

The decision was part of a wider strategy to decentralize social spending and focus central government resources on building roads and railways to boost economic growth.

In an interview with Reuters, the U.N. Secretary General's Special Envoy for AIDS in Asia-Pacific, J.V.R. Prasada Rao, warned "primitive" management by states would "ruin the program."

"When the new infections start rising, all the good work that has been done will be washed away," said Rao, who said he based his view on interactions with several federal and state AIDS officials in the last six months.

HEALTH WORKERS LEFT UNPAID

Reuters reported in March that government data and letters obtained under right to information legislation showed state treasuries were delaying payments and thousands of health workers had gone unpaid for months.

In letters seen by Reuters, some states have cited a lack of clarity about how much they need to contribute to the program under the new arrangement as a reason for delayed payments, and overall shortage of funds. Experts and state health officials also blame delays on slow bureaucratic processes.

An official at the federal AIDS control department, part of the health ministry that oversees the program, said delays in states disbursing funds were still widespread, with payments in some cases three months late.

The AIDS control department official said there was a risk of a rise in new infections if the delays continue, but added such a scenario was at least a year away.

The health ministry did not respond to Reuters' requests for comment on Rao's remarks.

Top officials in the ministry were concerned about the slowdown in releasing funds, according to letters seen in March and May.

INFECTIONS AVERTED

India's free HIV/AIDS drugs program, launched more than two decades ago, has been highly successful.

The World Bank estimates India's policy of targeting sex workers averted 3 million infections with HIV, the virus that causes AIDS, between 1995 and 2015. Still, UNAIDS estimates India accounted for most of the 340,000 new infections in the Asia-Pacific region last year.

India's last nationwide AIDS estimates were released in 2012. Data for the next assessment is still being collected.

Under the new funding arrangement, states are given a larger share of federal taxes but are no longer obliged to earmark funds for social schemes.

Rao said the flow of funds has improved marginally in recent months after complaints from AIDS workers, but he urged states and politicians to do more.

"We are getting complacent to the success," he said. "If we have to achieve the new goal of ending AIDS by 2030, you have to commit more resources."

In the western city of Mumbai, Manoj Jani, project director of an organization working with sex workers under the AIDS program, said his 23 staff were demoralized because they have not been paid for four months. AIDS tests have been curtailed.

"Workers are not able to travel for testing activities due to funding issues," Jani said. "We never thought we would see such a day."

(Reporting by Aditya Kalra; Editing by Frank Jack Daniel and Alex Richardson)