Greece's new leftist-led coalition government has formally assumed its duties, pledging to enforce creditor-demanded spending cuts and reforms while softening the pain on an austerity-weary population.

Labor Minister George Katrougalos says the new administration elected Sunday has to focus on the reforms that were a key condition for the latest in a series of international bailouts keeping the country afloat.

He spoke after a swearing-in ceremony Wednesday for Prime Minister Alexis Tsipras' new government, which retained the core of his previous Cabinet with a few tweaks.

These included Yiannis Mouzalas, the widely-respected immigration minister in the caretaker government appointed before the elections, who will remain in his post.

Immigration is a key challenge for Greece, which has received more than 260,000 refugees and economic migrants so far this year.