BUENOS AIRES (Reuters) - Argentina's Senate voted in favor of a bill on Wednesday that grants power to the government of President Alberto Fernandez to handle a massive debt restructuring of bonds issued in foreign currency.

The bill, which was approved by the lower house on Jan. 29, was passed unanimously by the Senate.

The crisis-stricken South American nation is grappling with about $100 billion in sovereign debt it is seeking to restructure with its creditors, including the International Monetary Fund, which has a $57-billion financing package with the country. New center-left President Alberto Fernandez has said that Argentina will struggle to pay its debts until it can grow its economy.

"Approving this bill means showing a gesture of national unity to strengthen the negotiating position of the government in the framework of debt restructuring," said Senator Lucila Crexell, an opposition lawmaker.

The senate's stamp of approval for the debt bill followed talks this week between IMF Managing Director Kristalina Georgieva and Argentine Economy Minister Martin Guzman ahead of a conference of economists in Vatican City hosted by Pope Francis.

Guzman told the conference on Wednesday that Argentina would under no circumstances continue servicing debt that was unsustainable and that pushed the country deeper into recession.

An IMF mission will come to Argentina to continue talks on Feb. 12.

(Reporting by Eliana Raszewski; Writing by Cassandra Garrison; Editing by Sonya Hepinstall)