The incident happened at A G Thomson and Sons on Spott Road, at some point between 2.30am and 3.15am on Thursday 1st February.
The suspects broke into a secure yard and stole a low loader HGV trailer by hitching it up to a white HGV cab. They are believed to have driven off towards the A1.
Officers are now keen to speak to anyone with information that can assist them with their inquiries or have seen this vehicle please get in touch.
Community support sergeant Scott Nicolson said: “We are continuing with our inquiries and are liaising with our counterparts in Northumbria, as we believe the trailer may have been used to steal a large excavator in the Berwick-on-Tweed area.
“The trailer has been described as distinctive and unique and we are hoping members of the public may have seen it since it was stolen on Thursday.
“We are keen to hear from anyone with information that can assist us with our investigation.”
Anyone with information is asked to contact police on 101 quoting incident number 0491 of 01/02/2018 or anonymously to the charity Crimestoppers on 0800 555 111.