LA PAZ, Aug 22 (Reuters) - Bolivia's government expects a boost in its credit rating in international capital markets after finalizing its last repayment installment for a 2013 sovereign bond, officials said on Tuesday.

The repayment marked the last installment of the $500 million loan.

Economy Minister Marcelo Montenegro confirmed the payment of $188 million, noting negative market reactions earlier this year over fears it might fail to pay.

"That was one of the reasons why the risk rating agencies, three, four months ago, lowered our rating citing the high risk Bolivia would not pay its bond. Now I want to hear from the rating agencies. What do they say?"

Between March and April the three major credit rating agencies - Fitch, Moody's and S&P - downgraded Bolivia's ratings, reducing its score for long-term sovereign debt to B- from B, while citing a deterioration in the government's external liquidity.

In June, the South American country's external debt rate stood at 29.2%, which Montenegro described as a "reasonable" level.

The external public debt that Bolivia has with international lenders totals some $13.3 billion. (Reporting by Daniel Ramos; Writing by Isabel Woodford; Editing by Alistair Bell)