(Adds breakdown of Buenos Aires inflation, analyst comment)
By Sarah Marsh
BUENOS AIRES, May 15(Reuters) - Argentina said on Friday inflation slowed in April but the annual rate remains stubbornly high and question marks over the credibility of government data mean it will likely have little impact on fiery protests demanding wage hikes.
Inflation in Latin America's third-largest economy eased to 1.1 percent on the month from 1.3 percent in March, according to official figures. That took annual inflation to 15.8 percent, much lower than private estimates of more than 20 percent and still one of the highest levels in the world.
Despite a revamp of its consumer price index last year in an effort to win back the trust of investors, Argentina remains widely suspected of manipulating official inflation data.
The government's monthly figure for April was less than half the 2.4 percent registered by Buenos Aires city. Its annual figure also came in well under the capital's 27.1 percent.
"After months of gradual convergence between official and alternative inflation figures, these showed a marked divergence during April," said Mauro Roca at Goldman Sachs.
"We estimate that annual inflation will progressively increase to 30.6 percent by year-end."
Inflation has eaten away at workers' purchasing power over recent years, with wages struggling to keep up with price hikes that many economists estimate hit around 35 percent last year. That contrasted with the official estimate of 24 percent.
With presidential elections due in October, workers are determined to make their wage hike demands heard by politicians courting votes, and as salary negotiations rage on in various sectors many are taking their demands to the streets.
Metallurgical workers banged drums and blew horns outside the labor ministry in Buenos Aires this week while construction and soy-crushing workers in the grains hub of Rosario went on strike, slowing exports.
Although President Cristina Fernandez cannot run for a third consecutive term, she will want to avoid protests getting out of hand in a way that might hurt the future ruling party nominee.
The powerful CGT umbrella labor organization said on Thursday it would join a general strike in June spearheaded by transport unions in demand of higher salaries and a tax cut.
They had held such a strike in March that ground public transport networks to a halt, paralyzed activity in the port of the grains powerhouse and at banks.
The data released on Friday showed consumer prices had risen 4.6 percent in total so far this year. (Additional reporting by Eliana Raszewksi and Hernan Nessi; Editing by Diane Craft, Andrew Hay and Ted Botha)