This is the first time that 2m points have been offered as a single prize and is the result of gas supplier BOC's participation in the Nectar Business customer loyalty programme.
During July and August, eligible customers spending more than £75 on gas, or £50 on equipment (gas equipment, welding products or safety gear) with BOC, will automatically be entered into the prize draw.
All qualifying purchases will receive double points during the two months.
The winner will be announced at the end of the promotion and will be invited to a special presentation later this year.
Nectar Business is a UK business loyalty programme that allows Small Medium Enterprises to collect points on their everyday business expenditure.
BOC has been a sponsor of the Nectar Business programme since October 2007.
Sarah Martin-Law, BOC channel manager, said: "We would like to reward our customers for their continuing business, but we also hope that an extra incentive like this may encourage new customers to try our products.
"We believe that once they have experienced the product quality and level of service that BOC offers, they will want to stay -- even after the prize draw comes to an end!"
There are currently 500,000 companies collecting points with Nectar Business, including Viking Direct, Business Solutions from the Carphone Warehouse, EDF Energy and Thomson Local.
Nectar points can be spent on rewards for the business such as laptops, telephones and the latest hi-tech equipment, or on treats for yourself or your team such as days out to Alton Towers.