LISBON—Portugal's new government will accelerate some austerity measures to narrow the country's budget deficit, after determining that the previous administration's efforts in the first quarter didn't go far enough, two government officials said.

The government on Tuesday released its austerity program for the next four years, saying it will "be more ambitious" and go beyond terms set out under the €78 billion ($111.43 billion) bailout arranged with the European Union and international lenders.

The...