Crude oil prices fell on Thursday as weak Japanese and Chinese economic data fuelled concerns that low levels of investment could further erode already slow growth in Asia.

Japan's core machinery orders, a volatile data series regarded as an indicator of capital spending in the coming six to nine months, fell 3.6 per cent in July, official data showed.

That was much worse than a 3.7 per cent increase expected by economists, and followed a 7.9 per cent month-on-month decline in June.

For Asia's biggest economy China, analysts already expecting a further slowdown in growth at its lowest in a generation keep receiving confirmation of their outlook.

China's producer price index fell 5.9 per cent in August from the same period last year, its 42nd consecutive month of decline and the biggest drop since the depths of the global financial crisis in late 2009, data showed on Thursday.

Benchmark Brent crude oil futures fell by almost 1.5 per cent to $46.90 per barrel at 0318 GMT. US crude futures were also down 1.5 per cent at $43.48 a barrel.

Oil prices have fallen by more than 50 per cent since June 2014, when soaring global output began to clash with slowing economies in Asia, the main growth engine for commodities over the previous several years.

The weakening in Asia's economies and commodity demand is having far-reaching effects.

On Wednesday, Standard & Poor's downgraded Brazil to a junk-grade credit rating, just seven years after it first won an investment-grade rating. Brazil, one of the main commodity exporters to China and a member of the so-called BRICS emerging economies - Brazil, Russia, India, China and South Africa - was until recently seen as one of the key drivers of the global economy.

The oil price fall was compounded after the Organization of the Petroleum Exporting Countries (Opec), led by Saudi Arabia, decided last November to keep output high in favour of market share over prices.

"In the first half of 2015, Saudi Arabia exported on average 4.4 million barrels per day (b/d) of crude oil to seven major trading partners in Asia, making up more than half of Saudi Arabia's total crude oil exports over that period," the US Energy Information Administration (EIA) said.

"Even as global crude oil prices fell in 2014 and 2015, Saudi Arabia increased production and kept its export levels high, enabling it to maintain its market share in these countries," the EIA added.  – Reuters