Alberta Premier Rachel Notley says falling oil prices won't force her government to back away from a royalty review or a hike to corporate taxes.

The benchmark price of a barrel of crude has fallen below US$40 a barrel for the first time since the end of the global economic crisis and oil prices have been falling solidly for eight consecutive weeks.

Notley says Alberta still has the best tax regime in Canada and profitable companies can pay a bit more when times are tough.

The Opposition Wildrose and the Canadian Association of Petroleum Producers have both urged the NDP government to hold off on raising corporate taxes and the royalty review.

Notley says the review will look both at present day and the future, when prices are expected to rebound.

She says the review will also take into account input from the industry.

"Alberta still has by far the most competitive tax regime in the country and so when times get tough, those who are profitable should be paying just a little bit more," Notley said.

"We'll be rolling out a jobs plan, an incentive plan, in the fall, understanding again that trying to diversify and stimulate the economy is a critical part to this."

Oil prices have fallen almost 60 per cent since this time last year and more than 34 per cent in the past three months.

The United States is churning out oil at an unprecedented pace, adding to the supply from Saudi Arabia and other OPEC nations.

What may be pushing prices this low, and possibly lower, is a steady drumbeat of economic data out of China suggesting that the world's second largest economy is slowing.