The move comes as part of a campaign by President Xi Jinping to show that the ruling Communist Party (CPC) is cracking down on corruption and waste.
Glitzy new government buildings, sometimes in impoverished areas, have been a source of public outrage.
The directive forbids luxury makeovers and expansions done under the guise of repair work, Xinhua news agency said.
The notice says some departments and local authorities have built huge government office compounds against regulations, tainting the image of the CPC.
Among the buildings that have attracted widespread disapproval in recent years is the western-style government office building in the city of Fuyang in Anhui province, in eastern China.
It reportedly cost 30 million yuan ($4.89m, Â£3.19m) to build and is referred to as the 'White House' by residents.
A state-owned drug company also caused outrage after photographs emerged apparently showing a building decorated to mimic France's Versailles palace, complete with gold-tinted walls and chandeliers.
Some government agencies have reportedly built luxury offices in seaside resorts where officials can stay for free or at deeply discounted prices.
The ban - described as an "across-the-board halt" - includes training centres, hotels or government motels, Xinhua said.
It also says government organisations should not receive sponsorship or donations towards construction projects, or collaborate with private companies.
"Banning the building of new government buildings is important for building a clean government and also a requirement for boosting CPC-people ties and maintaining the image of the CPC and the government," Xinhua quoted the directive as saying.
Tackling corruption has been President Xi Jinping's most high-profile policy since he became China's leader earlier this year.
He has warned that "corruption and bribe-taking by some party members and cadres" pose "severe challenges" to the Communist Party's rule.
China has banned the construction of government buildings for five years, according to state media.