The Tunisian General Labour Union (UGTT) urged President Kais Saied to expedite the appointment of a prime minister and form a government to face the urgent challenges the country is experiencing.
The body said it would not be possible to wait 30 days before a new government is named.
Tunisia's largest trade union's call came nine days after Saied dismissed Prime Mechichi Hichem Mechichi, suspended the government, and took over the executive powers, in a move his opponents described as a coup.
"We cannot wait 30 days for the government to be announced," said Sami Tahiri, a spokesman for the UGTT, one of Tunisia's most powerful political forces.
"We must speed up government formation to be able to face the economic and health challenges."
The president has not announced a roadmap to end the 30-day emergency period, which he later clarified could be extended for two months.
Sources told Reuters that the Central Bank Governor Marwan El-Abbasi and former Finance Ministers Hakim Hammouda and Nizar Yaiche are among prominent candidates for the position of prime minister.
Since his announcement on 25 July and takeover of executive powers, Saied has sacked 30 officials.