McDonalds is increasing the size of medium and large coffees for Super Gold cardholders.

It had previously sold any size McCafe coffee, tea or hot chocolate for $3 but it has now increased the price for medium and large to $4 and $5, respectively.

Massey University marketing professor Bodo Lang says it's likely there will be some upset people as a result of these changes.

"If the costs have increased dramatically, then, you know, price increases are warranted. But there's some really interesting research, particularly from Europe, that shows that price increases are well beyond the cost increases."

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