Japan's number one mobile phone operator NTT DoCoMo has said it will add a new application platform to its "i-mode" handsets this year as it tries to catch up with Apple's runaway iPhone success.

NTT DoCoMo will allow third-party individuals to develop applications for the company's 50 million "i-mode" users, spokeswoman Makiko Furuta said.

DoCoMo revolutionised Japan's mobile phone market with the 1999 launch of its i-mode service, which brought internet services to mobile phones. However, DoCoMo restricted the number of app developers, citing quality control issues.

But the recent emergence of open platform systems such as Google's Android and Apple's App Store for the iPhone and iPad has prompted DoCoMo to loosen its controls and allow individuals to easily create and offer apps and services.

"The open platform is everywhere in the world today and as the market changes, we would like to provide a platform similar to the smartphone for our i-mode customers," Furuta said. The new platform will be launched in November.

DoCoMo's lead is being nipped by the popularity of US-based Apple's iPhone, which accounted for 72 percent of smartphones sold in Japan in two years, according to a recent survey by Tokyo-based MM Research Institute Ltd (MMRI).

While that corresponds to five percent of the total mobile phone market, the figure illustrates that the Californian company is making inroads into Japan's notoriously tough-to-crack market.

DoCoMo's rival Softbank is the exclusive carrier for the iPhone in Japan.

In April DoCoMo launched Xperia, which allows users to download apps from Google's Android market.

The Japanese operator services a "DoCoMo market" for smartphone users that allows consumers to access apps from around the world.

Earlier this week NTT DoCoMo said it aimed to release an electronic book by next spring to compete with Apple's iPad, which has sold more than three million units worldwide since its April launch.