Turmoil in Iraq will drive gas prices to record highs over the weekend, predicts "Gas Guru" Dan McTeague.

On his website Tomorrow's Gas Prices Today, the former Member of Parliament warns that the cost per litre will jump two cents overnight, making gasoline the priciest it's been since September 2008.

"Sudden crisis in Iraq puts risk back on the table and increases speculative bets on all energy prices," says the site's one-week forecast. "Look to a sharp increase in fuel prices by Sunday, June 15."

Insurgents have seized several cities in Iraq, including the country's second-most populous, Mosul. Hundreds have been killed during the siege led by the group the Islamic State in Iraq and the Levant, sending the country's oil supply into a state of uncertainty.

Iraq is the second-highest exporter of crude oil in the Organization of the Petroleum Exporting Countries. OPEC controls 81 per cent of the world's oil reserves, according to their estimates.