Ghana's chief of state, Gen. I. K. Acheampong was ousted in a bloodless palace coup yesterday and replaced by his deputy on the ruling military council.

The sudden changeover was seen by U.S. officials as a response to Ghana's growing economic difficulties. It is not expected to result in any foreign or domestic policy changes and its main objective appeared to be an effort to deflect criticism of the military council's management of the economy.

Ghana is experiencing severe foreign currency problems that have led to shortages of consumer goods and energy. The country's oil refinery ran out of crude last week.

An official Ghanaian statement said Acheampong, 46, who took power in a bloodless coup six years ago, resigned as head of state and simultaneously retired from the armed forces.

"This decision has been taken to ensure the unity and stability of the nation," the statement said without providing other details.

The new leader was identified as Lt. Gen. Fred Akuffo, Acheampong's deputy on the six-member military council and chief of Ghana's defense staff.

American officials said Accra, the capital, was taken by surprise by the military council's announcement. But they said the city was calm and there was no evidence of any major troop movements. Ghana's border with Togo was reported to have been sealed off.

Apart from responding to popular unhappiness with the council's economic policies, these officials said yesterday's move also indicated disagreement among senior military officers over Acheampong's plan to move gradually toward civilian government.

The plan to devise a new African political system capable of reconciling military and civilian claims to power was put to a referendum last March but won the support of only slightly more than half the voters. A secret ballot count led to charges by the civilian opposition that the results were rigged.

The opposition is made up of students, professionals and some intellectuals associated with the deposed former president Kwame Kkrumah, who led Ghana to become the first former African colony to gain its freedom in 1957.

Since Nkrumah's overthrow in 1966, Ghana has passed through two periods of military rule and one shortlived civilian government. Its chronic economic problems have intensified in recent years. In 1977, inflation in Ghana reached 150 per cent and that along with governmental mismanagement and graft led to riots by students and opposition factions last summer.

The West African nation is roughly the size of Wyoming and has population of about 10 million. It is rich in mineral resources, including diamonds, manganese, gold and bauxite. It is also the world's leading cocoa producer accounting for roughly one third of world output.