The scheme allows customers to swap vouchers for rewards tokens which can be spent with commercial partners such as Pizza Express and London Zoo .
From Monday the retailer will offer its 16m Clubcard holders three times the value of vouchers with its commercial partners.
Previously, some offered twice the value, but others offered three or four times the value.
Vouchers could be used restaurants such as Pizza Express, Prezzo and Zizzi for four times their face value, but can now only be used for three times their face value.
Tickets for attractions such as London Zoo, Shakeseare’s Globe and the Tower of London are also now available for three times the value of Clubcard vouchers, down from four times.
On its website, Tesco says: “We’re simplifying the Clubcard rewards you can collect through the majority of our Reward Partners. Previously, you could either get 2x, 3x or 4x the value of your Clubcard vouchers – but starting from 15 January 2018, we’re making everything 3x the value.
“So you won’t have to keep checking whether you’re getting 2x, 3x or 4x the value depending on which reward you’re claiming; everything will be 3x.”
But only a small number of retailers, including National Express, redspottedhanky and Megabus gave twice the value of vouchers.
Some retailers which offered twice the value but now have to offer three times the value, including Pickfords Removals and Red Letter Days have announced they will be leaving the scheme in the next month. figleaves.com, Spafinder and Treatwell have disappeared from the website already.
Tokens for Goldsmiths and Hotels.com are not affected, remaining available at three times the value of vouchers.
Clubcard holders were not impressed by the changes. “As I have £100 in Clubcard coupons that were “worth” £400 in vouchers yesterday and are now only worth £300 I feel like a victim of a pickpocket,” wrote Stephen Ellerington on Twitter. “Straight devaluation/cost-cutting measure from Tesco,” added Neil Spellings.
“Understanding the variable pricing was hardly rocket science when the website worked it all out for you!”
Clubcard vouchers will still be worth their face value when they are spent on groceries or anything from Tesco Direct.
By the end of February, rewards tokens will be sent by email, rather than by post.
An email sent to Clubcard holders said: “We’ve listened to our customers and simplified our Clubcard Reward partners so that they’re more straightforward for everyone.
“From 15 January, we will offer customers three times the value of their vouchers with over 100 Clubcard Reward partners including days out, weekend breaks, holidays and more.”