(Adds details on broader economy, new taxes, oil price)
By Sarah Marsh and Daniel Ramos
LA PAZ, July 6 (Reuters) - Bolivia may issue up to $1 billion in international bonds this year to help finance new state-run industries and roads, but uncertainty over when the United States will raise interest rates is complicating timing, its economy minister said.
Luis Arce said the Andean nation wanted to broaden its industrial base to add more value to natural resources already being exploited and tap new mineral reserves. This would help ease Bolivia's dependency on gas exports and reduce its vulnerability to global commodity prices.
Arce maintained his forecast that the natural gas-producing economy would grow 5 percent this year and said the figure would edge slightly higher in 2016 as new factories start exporting urea and potassium chloride, ingredients for fertilizer.
"If there is a good moment, we will issue," Arce said in an interview over the weekend. "We are looking at the external conditions and there is a lot of uncertainty. The United States are not giving a very clear signal as to what they will do." The Greek debt crisis had also clouded the outlook, he said.
Arce said investors were keen for longer-term paper and that the next issuance would likely carry a 10- or 15-year maturity. Bolivia returned to global credit markets for the first time in nearly a century in 2012, selling $500 million in 10-year bonds. The country has a relatively light debt burden.
"Right now our external debt is 18 percent of GDP. We have space for more," he said.
If the debt issuance falls through, Arce said hard currency reserves were deep enough to sustain President Evo Morales' brand of "indigenous socialism," which has vastly expanded the role of the state in the economy, even at low oil prices.
Bolivia's economy has tripled in size during the nine years under Morales, a prominent member of South America's leftist bloc who expounds fiery anti-capitalist rhetoric and has nationalized key industries such as oil and gas.
It remains, however, one of the region's poorest nations and will receive Pope Francis later this week.
In the high-altitude capital, La Paz, office towers, shopping malls and restaurants have mushroomed. Arce, who was wearing a breast pin of the Marxist guerrilla leader Ernesto "Che" Guevara, is widely considered the architect of Bolivia's economic boom.
He has won plaudits from Wall Street for his prudent spending of a natural gas bonanza to finance welfare programs and build new roads and schools. But now the global slump in oil prices is eroding Bolivia's gas export earnings.
Gas accounts for roughly half Bolivia's total exports, according to the U.S. CIA Factbook. Arce said exports would tumble 18 percent this year after Bolivia posted its first quarterly trade deficit in 11 years in the first three months of 2015.
But he noted Bolivia was "comfortable" with crude prices between $55 and $60 per barrel and anticipated a neutral trade balance for 2015.
Arce cut his inflation forecast for 2015 to 3.5 percent from 5.5 percent previously due to an increase in local agricultural production and low international energy prices. However, inflation would accelerate to between 4.5 percent and 5.5 percent in 2016, he said.
In a bid to broaden the tax base, Arce said the government was working to regulate Bolivia's vast informal economy, including coca leaf production.
A key ingredient in cocaine, the unprocessed leaf is still widely chewed, legally, in Bolivia and other Andean countries.
"We are going to present a law so that they also pay taxes, and they are willing," Arce said. (Reporting by Sarah Marsh and Daniel Ramos; Editing by Richard Lough, Chizu Nomiyama and Meredith Mazzilli)