Kiwi chocolate company Whittaker's will increase the price of their chocolate blocks from next week.

The company said in a brief statement that rising costs means there is no other choice.

"From Monday we sadly have to raise our prices. Why? Because our costs have been steadily rising."

The rise in cost follows Cadbury's lead, who announced in February their block sizes would be decreasing.

"Rather than raising the recommended retail price, we've made the call to reduce the size of our Cadbury family blocks," the company said in a statement.

Whittaker's seems to be taking the other option, ensuring Kiwis their block would stay the same size.