Christmas has come early for a group of enterprising burglars, after they broke into a meat factory and stole truckloads of holiday hams over the weekend.

The thieves even taunted the owners of Zammit Ham and Bacon Curers, in Sydney's north-west, by leaving a large note scrawled in texta on a wall inside the meat warehouse that read: "Thanks ... Merry Christmas."

The thieves cut a hole in an exterior wall at the warehouse, on Nirvana Street in Pendle Hill, and removed 16 pallets - each weighing about a tonne - of double-smoked hams, Christmas leg hams, banjo hams and oven roasted turkey breast, co-owner of the warehouse Anthony Zammit said this morning.