Namibia has banned all foreign travel by public officials as the southern African country tries to rein in government expenditure.

The ban will be in place until at least February, the country's presidency said in a statement on Wednesday.

"No request for outbound travel by ministers, deputy ministers and other political office bearers will be considered until after the end of February," the statement said.

"This directive is specifically in the interest of curtailing public expenditure," the statement added.

The country's economy is heavily dependent on mineral exports, but the global price contraction in the commodity market has affected its main exports, uranium and diamonds - leading to severe budget cuts.

The presidency said the directive applies with immediate effect.

The cash crisis has led to President Hage Geingob grounding his presidential jet. Last week, the president took a scheduled commercial flight to attend the African Union summit in Addis Ababa.

The country's defence ministry will send thousands of soldiers on leave next month because the army has run out of money to feed them or to pay water and electricity bills, The Namibian, an independent newspaper, reported Wednesday. At least seven military bases will be affected by the move, the report added.

Soldiers who are currently on leave have been told not to report back to work.

In August, Moody - the credit rating agency - downgraded Namibia's debt status to junk.