Alcoa believes global aluminum demand is likely to grow this year at the slowest pace since the global recession in 2009, a new sign of the global slowdown.

Alcoa chief executive Roy Harvey said in a note to analysts that the company expects global aluminum demand to grow 3 percent to 4 percent this year, the slowest pace since the global market shrank in the wake of the financial crisis.

Aluminium is often seen as a barometer of the health of the global economy because of its use in everything from construction to aerospace to car manufacturing.

Harvey promised an urgent response to these developments in the coming year.

Alcoa on Wednesday reported fourth-quarter revenue that fell 37% from the same quarter in 2017, but was better than analysts expected.

Excluding one-time items such as restructuring costs and non-recurring taxes, the company reported adjusted net income of 66 cents per share, above the average estimate of 62 cents.

Free cash flow excluding capital expenditures was $387 million in the fourth quarter, up 27 percent from the same period in 2017. Alcoa shares fell 1.3 percent to $28.60 in extended trading.

The slowdown in global demand growth reflects expectations for Chinese demand growth of 4-4.5 per cent, a significant reduction from Alcoa's 2016 forecast of 6.5 per cent growth that year.

LME aluminum is down 16% from its high in early October. Alcoa expects aluminum shipments to fall to 2.8 to 2.9 million tons this year from 3.3 million tons in 2018.

Harvey said the company would focus on "what we can control, continue to improve our operations, be nimble in meeting challenges, and take full advantage of opportunities in the year ahead".

Alcoa also said in its earnings report that the aluminum market output gap will expand to 2.1 million tons this year; The supply gap for 2018 is 1.7 million tons. The company also expects the alumina market to shift from oversupply to undersupply this year.