Since March 1, the number of people looking to buy a new 03 registered model has slumped by 35 per cent, the company claims.
CarPriceCheck believes between 60,000 to 80,000 sales will be lost in March and April alone.
Steve Evans, managing director of PriceCheck.com said: "Car buying activity was holding its own during the latter stages of February as interest in the new registration took hold.
"But as the Iraq crisis has gathered momentum, consumer interest literally seems to have fallen away.
"From experience of the September 2002 registration trend, we know that business and fleet sales are likely to show a significant jump followed by an increased availability of pre-registered cars in about three to four months' time."