Blockades of Irish oil infrastructure, triggered by a more than 20 per cent rise in diesel prices since the outbreak of the US-Iran war, have created a very severe situation that will damage the economy, Micheal Martin said on Friday.
Industry group Fuels for Ireland said more than 100 petrol stations had run out of fuel and that number could rise to 500 by Friday evening.
"The situation is very severe now. I don't think people out there perhaps realise the gravity of the situation," Martin told RTE in an interview.
"We are now on the precipice of turning oil away from the country," he said, citing a tanker that was unable to unload at Galway Port and a halt in refining at the Whitegate oil refinery near Cork.
"It is unconscionable, it is illogical, it is difficult to comprehend."
Martin said the police and army were on stand-by to help clear the protests if necessary and said that "very clearly the law will be upheld".
But he also called for dialogue to resolve the issue.
Delivery firm DPD said it was suspending services in Ireland on Saturday due to the protests.
The government last month announced a 250 million euro ($A414 million) package to temporarily cut taxes on petrol and diesel to cushion the knock-on cost of the Middle East conflict but protesters have called for stronger measures including a price cap.
