Guinea's military junta, which seized power over the weekend, said on Thursday that it has ordered the central bank and other banks to freeze all government accounts.
On Sunday a group of special forces soldiers said they ousted President Alpha Conde over concerns about poverty and endemic corruption.
The banking freeze was aimed at "securing state assets", a junta spokesman announced on the national broadcaster.
"This includes public administrative and commercial establishments in all ministries and the presidency, presidential programmes and projects, members of the outgoing government as well as senior officials and administrators of state financial institutions," the spokesman said.
A mining boom propelled strong economic growth during Conde's decade in power, but surveys suggest Guineans thought corruption has increased in recent years, while dissatisfaction with the economy and living conditions has also risen.
A delegation of West African leaders was due in Guinea on Friday to assess the situation following the coup that has raised fears of a backslide towards military rule in the region.
Leaders from the 15-member Economic Community of West African States (ECOWAS) condemned the coup on Wednesday and called on the military to release Conde, who was arrested during the takeover.
They also suspended Guinea's membership in ECOWAS, the region's main political and economic group, but fell short of threatening sanctions.
ECOWAS president Jean-Claude Kassi Brou and Ghana's foreign affairs minister, Shirley Ayorkor Botchway, will lead the bloc's delegation in Guinea, but the bloc provided few details.
One high-ranking regional official said ECOWAS wanted the junta to appoint a "credible" civilian prime minister as soon as possible to help steer Guinea back towards constitutional order.
The bloc had been due in the Guinean capital, Conakry, on Thursday, but two sources in Guinea's junta said the delegation was delayed to Friday.
ECOWAS did not immediately respond to calls for comment.
It could face a challenge trying to influence events in Guinea after struggling to impose its will in Mali, also in West Africa, where two coups since August 2020 have left military leader Assimi Goita in charge despite repeated ECOWAS warnings.
Those two coups and another in Chad in April have renewed concerns about the return of military rule in a region that had made strides towards multi-party democracy since the 1990s.
Life in the capital Conakry has started to return to normal, with traffic and street hawkers clogging the streets.
The only roads still manned by military checkpoints were those leading towards the Kaloum peninsula, the capital's administrative centre and home to the presidential palace.
Fears that the power struggle could hinder Guinea's production of bauxite, a mineral used to make aluminium, have begun to ease. The country's largest foreign operators say they have continued work without interruption.