Recently listed fuels supplier Viva Energy has again downgraded its profit guidance for 2018, citing weakness in Asian refining margins, as warned that profit from refining this first half of 2019 may also miss prospectus forecasts.

Underlying earnings before interest, tax, depreciation and amortisation for the year ended December 31 in the refining business are now expected to be about $125 million, compared to the November guidance of $150 million, Viva said on Friday.

The company's shares were down 1.4 per cent at $1.79.

Qantas Airways shares are down 2 per cent to $6.00.

Credit Suisse has cut its rating on the airline to neutral from outperform and lowered its target price to $6.70 from $7.35.

The broker says that weak Aussie consumer sentiment along with increasing geo-political uncertainty is likely to weigh on demand for air travel.

"In the current less certain demand environment, we are less confident that the board will announce an additional buyback at the H2 FY19 results," the broker said.

The US dollar is hovering at a near six-week high against the euro on Friday,

The euro steadied at around $1.13, after dropping 0.7 per cent overnight to trade at its weakest level since December 14. The euro is down 0.5 per cent this week.

European Central Bank President Mario Draghi said on Thursday that economic risks have moved to the downside in Europe and near-term data is likely to be weaker than previously anticipated.

Survey data showed on Thursday that business activity across the euro zone expanded at the slowest pace since 2013 at the start of this year.

- Reuters

The ASX is powering into the afternoon, with the benchmark up 44 points, or 0.8 per cent, at 5909.

Iluka Resources jumped 9.1 per cent after reporting mineral sands revenue of $318.2 million, from $245.4 million.

Energy stocks climbed after a jump in oil prices, with Woodside, up 1.1 per cent, Origin Energy, up 1 per cent, and Santos, up 1.5 per cent.

On the downside, Resmed dropped 11.5 per cent after its second-quarter revenue missed analyst estimates.

AMP shares were down 6.5 per cent after the wealth management firm slashed its dividend.

The Australian energy index hit its highest level since November today.

The sector climbed after a rally in US oil prices overnight on the threat of US sanctions over Venezuela.

Energy companies on the move in Australia included Woodside, up 1.1 per cent, Origin Energy, up 1 per cent, and Santos, up 1.5 per cent.

Oil futures in New York gained 1 per cent on Thursday. WTI recently traded up 7 cents at $53.20 a barrel while Brent futures advanced 5 cents to $61.09 a barrel.

The gains for oil came as political turmoil continues to grip important oil producer Venezuela.

AAP reports that President Nicolas Maduro on Thursday ordered all of Venezuela's diplomats home from the United States and defiantly closed the country's embassy as relations between the two nations rapidly collapsed.

Tensions have soared between the two nations after the Trump administration recognised opposition leader Juan Guaido, who claimed Wednesday to hold the presidency and vowed to remove Maduro, calling him a "dictator," according to AAP.

While the Australian dollar continues to wallow, the British pound is surging. Sterling is trading over $1.30 against the US dollar this morning, hitting its highest level since early November.

Sterling traded at $1.31, while the Australian dollar is at US70.87¢ against the greenback.

Bloomberg has attributed the gains in sterling to a report in The Sun newspaper that Northern Ireland's Democratic Unionist Party - which provides crucial support for UK Prime Minister Theresa May's government in Parliament - has agreed to back her new Brexit deal.

Thursday's trading session was anything but ordinary for Singapore's traders, with a $US41 billion crash in the city's biggest stock, Bloomberg reports.

Jardine Matheson Holdings, the flagship investment firm of a 186-year-old conglomerate that hadn't posted a double-digit stock decline since April 2009, plunged 83 per cent in pre-market trading.

While the drop reversed almost as quickly as it happened, some 167,500 shares changed hands at prices less than a quarter of the previous day's close,

Resmed shares are under selling pressure today after the health care firm released second -quarter results.

Resmed shares were recently down 9.8 per cent at $14.84, the worst performer in percentage terms on the Australian benchmark.

The firm's revenue in the quarter of $651.1 million missed analyst estimates for revenue of $672.9 million, according to Reuters.

US earnings season continues apace, with Intel Corp late Thursday forecasting current-quarter revenue and profit below analysts' estimates as it missed fourth-quarter sales estimates, Reuters reports.

Intel was hit by a slowdown in China and sluggish demand for its data centre and modem chips. The company's shares fell 6.7 percent in after-hours US trading on Thursday.

Until Intel's report was released, sentiment on the chip sector had been recovering this week after better-than-expected quarterly results from Texas Instruments, Xilinx and Lam Research Corp.