UPDATE 1-Argentina inflation steady at 0.9 pct in September

* Twelve-month inflation unchanged at 10.0 percent

* Reuters poll put real inflation at 1.9 percent

* Medical, clothing costs clock biggest increases

BUENOS AIRES, Oct 12 (Reuters) - Argentina reported September inflation of 0.9 percent on Friday, unchanged from the previous month and well below the 1.9 percent increase estimated by economists in a Reuters poll.

The INDEC statistics agency's consumer price data has been widely discredited as too low for five years and independent estimates tend to double or even triple the official number.

Argentina's economy has slowed sharply this year after growing at China-like rates for most of the last nine years, but high price rises are entrenched and expectations for annual inflation are around 30 percent, private data shows.

Reflecting the gaping difference between real and official inflation data, wages in the formal economy and state welfare benefits have been rising at a rate of more than 20 percent.

Loose monetary policy, including the rapid expansion of the money supply, is fueling consumer demand despite cooling economic activity, the four analysts surveyed by Reuters said.

They estimated last month's real inflation at 1.9 percent, with a range of forecasts from 1.8 percent to 2.0 percent.

INDEC said 12-month inflation through September remained at 10.0 percent. That was far below the 20 percent to 25 percent rate estimated by independent economists and consumer groups.

"Inflation of about 25 percent per year is totally instilled in the economy, so everything from school fees to health insurance payments is going up by 20 percent or 25 percent," said Fernando Freijedo, an analyst at the Buenos Aires-based consulting firm Espert and Associates.

The state agency said the biggest price gain last month, 1.9 percent, occurred in the medical care category.

Clothing costs rose 1.6 percent, while the heavily weighted food-and-drink sector climbed 0.8 percent last month, up from 0.6 percent from August.