Yoo Il-Ho's comments came after parliament voted Friday to impeach Park, stripping away her executive powers over an influence-peddling scandal and opening up a new period of uncertainty for the country.
"The Korean government is mindful of the severity of the current situation," Yoo told foreign reporters.
"I promise you that we will do everything we can to keep our economy strong and stable."
South Korea has been struggling with soaring household debt, low birth rates and rising youth unemployment with its economy expanding at the slowest pace in recent years.
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"The biggest vulnerability from the political issue is that it will put a dent on our sentiment," he said, adding the finance ministry aimed to "successfully navigate through these tough times".
The scandal that has engulfed the president and paralysed her administration has focused on her friendship with long-time confidante Choi Soon-Sil.
Choi has been charged with meddling in state affairs and using her presidential Blue House connections to force dozens of conglomerates to donate around $70 million to two foundations she controlled.
Yoo, who acknowledged the unhealthy ties between the state and South Korean firms, denied any "direct involvement" of the finance ministry in the ongoing scandal.