The result of Sunday's voting has the potential to upend relations with Beijing or Washington, and could even jeopardize Ecuador's continued use of the U.S. dollar.

Long lines formed at some polling stations in the capital Quito, as measures to reduce the risk of Covid-19 infection slowed the pace of voting.

Voters face a stark choice between embracing painful economic change or harking back to a prior era of fiscal largesse. There are 16 candidates, but polls suggest it's a neck-and-neck race between Guillermo Lasso, a conservative banker and self-made millionaire and Andres Arauz, a socialist economist.

"What's at stake is fiscal austerity versus a return to the debt cycle", said John Polga-Hecimovich, who teaches political science at the U.S. Naval Academy in Annapolis, Maryland.