Hyundai and Kia are raising the prices of new models launched in the US this month in an attempt to head off the challenge posed by a stronger Korean won which is undermining the group's profitability.

Kia started sales of its new 2014 Sorento SUV in the US this week and the price range has risen from US$23,150 and $33,400 to between $24,100 and $39,700.

Hyundai has also raised the price of its 2013 Sonata Hybrid by up to $4,700.