The market for mobile pornography is set to experience strong growth, according to industry insiders.

Web searches for 'iPhone porn' have increased nearly fivefold in the past six months, according to Google Trends.

The adult industry is hoping for an explosion of interest in such content online thanks to the devices.

Devan Cypher, a representative for San Francisco-based Sin City Entertainment, told Time magazine that the iPhone is "by far the porn-friendliest phone".

Research has shown that around a third of iPhone users watch video on their handsets, nearly 10 times the number who watch video on other brands of mobile phone.

IPhone users also typically spend five times as much on mobile entertainment, and three-quarters of iPhone owners are men with above average incomes, a traditional market for the pornography industry.

Apple has traditionally taken a firm line on pornography, banning adult content from its online stores. It will also be doing what it can with the iPhone.

"Our iPhone 2.0 software will give customers the opportunity to turn on parental controls," said Apple spokeswoman Jennifer Bowcock.

However, given the increasing technical sophistication of the pornography industry, there may be little that can be done to stop it as the new iPhone's fast streaming capabilities and large screen make it a prime target.

"There are a few hundred iPhone porn sites now in use," said Farley Cahen, vice president of business development at adult industry trade organisation AVN Media Network.

"A huge portion of the $13bn adult market has been reliant on physical distribution. That business model is shifting to downloadable and streaming content."