The International Monetary Fund has extended its $1.34-billion (one-billion-euro) loan programme in Angola to March 30 to allow time for a final review before the last payout, it said on Thursday.

The IMF made the loan in 2009 to help the oil-rich southern African nation's government stay afloat after the oil price dropped. It was originally set to expire on February 22.

All but $133.6 million has been disbursed, but the IMF wants to carry out a sixth and final review of the government's economic performance before signing off on the payment.

"The final disbursement... would become available on completion of the sixth review, which the executive board is now expected to consider in late March 2012," it said on its web site.

The global lender voiced concern in December over a $32-billion gap in the government's accounts, about one-fourth of the country's gross domestic product.

President Jose Eduardo dos Santos' government denied the money was missing, putting the gap down to an accounting discrepancy.

The IMF said last month the gap appeared to have been caused by undocumented spending on infrastructure projects by the state oil company Sonangol, and that Angola was making "a very concerted effort" to sort out its books.