In less than a week the yellow.co.nz business search directory became New Zealand's most popular free iPhone application.

Launched on August 20th, 1737 unique users used the application in nearly 4000 sessions after just four days.

Yellow marketing director Kellie Nathan says the popularity of the application is a vote of confidence in the company's digital strategy.

The Yellow iPhone app provides location awareness via the iPhone's built-in GPS, mapping and directions functionality.

The application also has the ability to save businesses to users' contacts and email search results to others.