Police suspect a lorry stolen just hours before the theft of thousands of litres of diesel was used in the raid.
The 40ft articulated vehicle, which was taken in Donaghcloney near Lurgan, was spotted by security cameras in Co Down between 2am and 4.30am yesterday.
Police believe it was stolen for the purpose of the theft of 25,000 litres of fuel siphoned from tanks belonging to Tarmac Quarry Products at Craigantlet Quarry near Newtownards.
Petrol retailers have been warned to be on the alert after the second massive fuel theft in north Down in less than a week.
Police are trying to establish if the theft is linked to a similar theft in Crawfordsburn on July 21 when 7,000 litres of diesel worth over £10,000 was stolen from a petrol station.
Shortly after 7am yesterday, police received a report from staff at Craigantlet Quarry that the business had fallen victim to fuel thieves.
North Down DUP MLA Gordon Dunne said news of a second major diesel theft in the area so soon after the first had sent shockwaves through the community.
“There is now a very real problem with crime of this nature taking place and action must be taken by the police, assisted by the local community, in trying to prevent and deter such incidents occurring again in the future,” he said.
“These mindless thugs show no regard for the hard-working men and women who are struggling to keep businesses alive and providing much needed employment.”
The owners of the quarry did not wish to comment.
A police spokesperson said they are trying to establish if there is a link to the Crawfordsburn incident.
Following the Crawfordsburn incident, the Irish Petrol Retail Association (IPRA) said Northern Ireland fuel suppliers should be on high alert after a spate of such incidents in the United Kingdom and Republic.
Meanwhile, neighbourhood police officers on patrol in south Down yesterday afternoon discovered 22 pallets of drums full of stolen home heating oil.
The 14,000 litres of oil, found in the Cranfield area of Kilkeel, has an estimated value of around £20,000.
Police investigating two north Down diesel thefts are trying to track down an ERF articulated lorry with the registration WLZ 8023. It has a light-blue cab and dark-blue curtain trailer. They are particularly keen to hear from anyone who noticed large vehicles around the area of Craigantlet in the early hours of yesterday morning. They appealed to delivery drivers, or taxi drivers, who may have used the Belfast Road, Holywood Road, Dunlady Road or Carrowreagh Road overnight and who may have seen such vehicles to assist their inquiries.