Chancellor Angela Merkel of Germany vowed continued support for Portugal on Monday, seeking to reassure a European partner that fiscal overhauls would be rewarded with long-term growth and stability.

Even as finance ministers from the 17 euro zone countries gathered in Brussels to consider the release of €31.5 billion, or $40.1 billion, in aid for Greece, Ms. Merkel expressed confidence that the troika of international lenders that has bailed out both Greece and Portugal would issue a favorable report on Lisbon’s efforts at reforming its economy.