On the eve of its annual meetings in Bali, Indonesia, the fund on Tuesday projected a global expansion of 3.7 per cent this year and next, down from the 3.9 per cent projected three months ago.
"In Nigeria, inflation is projected to fall to 12.4 per cent in 2018 from 16.5 per cent in 2017, and to rise to 13.5 per cent in 2019".
"There are clouds on the horizon".
"We are concerned about the downturn in economic growth", noted Jubilee USA Executive Director Eric LeCompte.
The IMF added interest rates would need to be increased to deal with inflation but it warned the Bank of England to be flexible so it could change depending on the situation.
The Pakistani rupee on Tuesday was unofficially devalued by 7 per cent plunging to all-time low of 35.67 against the UAE dirham.
The IMF now expects South Africa's economy to expand 0.8 percent, down from a forecast of 1.5 percent in July.
President Donald Trump has slapped tariffs on US$250 billion in Chinese goods this year, and Beijing has retaliated with levies US$110 billion of American products.
The IMF warned that China's growth even risked declining by a full percentage point by next year in the event of a "worse-case" scenario, involving further tariffs coupled with a collapse in confidence by businesses and markets. Overall, global growth will remain steady - about 3.7 percent this year - and exceed that of 2012-2016.
The May federal budget forecast 3 per cent GDP in 2018-19 and the same the following financial year.
Several emerging markets had their forecasts cut, including Argentina, Brazil, Iran and Turkey, reflecting factors including tighter credit.
"Growth performance varies, however, across countries". The US growth forecast was cut by 0.2 percentage points in 2019 tp 2.5pc.
While tax cuts and increased spending have seen an immediate upswing in U.S. growth, the International Monetary Fund warned that the country could face an unwelcome "inflation surprise", which would prompt the Federal Reserve, America's central bank, to hike rates at a faster-than-expected pace.
An industry source who also tracks exports said October shipments so far were below 1 million bpd. The acceleration relative to 2016-17 reflects a more supportive external environment, including stronger global growth, higher commodity prices, and improved capital market access, following efforts to improve fiscal balances in the aftermath of the commodity price slump. "Inclusive fiscal policies, educationalinvestments, and ensuring access to adequate health care can reduce inequality and are key priorities", he said. "Policymakers must take a long-term perspective to address this malaise".