British Columbia's independent energy regulator will have the power to call oil company representatives as witnesses into an investigation of high gasoline prices in the province.

Premier John Horgan has tasked the B.C. Utilities Commission to examine the market factors that affect wholesale and retail gas prices, and he wants a report by Aug. 30.

Gas prices hovering around $1.70 per litre in the Metro Vancouver area have been the highest in Canada for several months.

Horgan says he's given the utilities commission broad terms of reference to conduct a fair and transparent investigation that would include concerns about competition and why recent gas refining margins for Vancouver have been more than double the Canadian average.

Liberal Leader Andrew Wilkinson has been calling on the New Democrats to reduce provincial gas taxes and has applied to participate in the investigation as an intervener.

Horgan says in a statement the terms of reference give the utilities commission the reach to investigate price fixing and gouging and to make recommendations.