The leftist Social Democrats and the centre-right Liberals formed a grand coalition government in late 2021 - together with a junior partner, the ethnic Hungarian UDMR - and agreed that the two main parties would rotate premiers. The Liberals' Nicolae Ciuca resigned as prime minister on Monday.
"That we are here to rotate prime ministers shows a new level of involvement and seriousness of the ruling coalition," Iohannis told reporters. "Romanians were promised stability and they are getting stability."
Ongoing negotiations over key ministries and jobs have already stalled policymaking and Romania is behind on reforms needed to unlock further tranches of European Union recovery funds, a key factor underpinning the eastern European state's economic growth.
Ciolacu reiterated plans to have a new government approved by parliament and sworn in on Thursday.
The new cabinet will face pay claims from various parts of the public sector, including healthcare, while budget revenue has so far this year underperformed targets.
The EU state holds presidential, general, local and European elections in 2024, when it must bring its budget deficit back below the European bloc's ceiling of 3% of gross domestic product.
The Romanian leu was down 0.1% against the euro on the day.
(Reporting by Luiza Ilie; Editing by Alex Richardson)
