JTI is giving retailers the chance to win 500 extra training packages to help them prevent underage sales.
The tobacco manufacturer had initially offered 50 packages but high levels of interest among retailers had prompted it to extend the initiative, JTI said.
The qualification, which is recognised by Trading Standards, the police and local authorities, enables stores and their staff “to become pillars of responsible retailing in their local communities”.
To enter, retailers need to log on to the website jtiadvance.co.uk before 25 November and take part in a short quiz, before entering their details to go into the prize draw.
Those retailers not already registered on JTI’s trade website should speak to their JTI representative or call JTI’s Customer Careline on 0800 163 503 to receive a Contact ID.
Winners of the competition will receive course materials for the BTEC Level 2 Award in Under Age Sales Prevention for each of their staff, worth £100 each.
They will also receive training from a former Trading Standards Officer at Under Age Sales Ltd who will prepare staff for the exam at a mutually convenient time.
The officer will supervise them in taking the exam, before marking it and posting it to Edexcel for the Award.
Tom Hirons, government relations manager at JTI, said: “We all agree that children should not smoke and should not have access to tobacco products.
“Offering retailers this qualification is part of our wider commitment to supporting retailers in making sure that under 18s cannot buy tobacco in their stores.
“Retailers should take advantage of this opportunity to win high quality training for their staff and protect their businesses by logging on to JTI Advance now to take the quiz.”