Phone carriers in Australia are mounting major marketing initatives in an effort to convert hundreds of thousands of people who purchased a new iPhone 4 two years ago this month on 24 month contracts.

A Telstra mobile executve said that “thousands” will  be eligible to upgrade their mobile phone this month. Both Optus and Vodafone are also mounting direct marketing campaigns in an effort to convert users to their network.

The surge in new phone replacements , which analysts have  dubbed ‘upgrade armageddon’, could benefit Samsung said a Vodafone executive due to Apple not having a new iPhone 5 untill September 2012.

Currently the Samsung’s Galaxy S3  is dominating Android sales with many former Apple iPhone users set to switch to the new Samsung offering due to a larger screen and faster processor said an Ovum research analyst.

In recent months mobile phones using Google’s Android system have collectively a grabbed a 56.9 percent share of the overall market in Australia, according to new figures from market research group Kantar Worldpanel ComTech.

Kantar claims Android’s share has increased to this level from 36.4 percent in June last year. It gives Apple’s iOS a current share of 30.5 percent, down from 36.9 percent in June last year.

No other OS is given more than 4.8 percent of the market. Biggest loser, in Kantar’s reckoning, is Research in Motion, down from 2.2 percent of the market to a claimed 0.1 percent.

The Apple phones are doing better in the US, where they have increased market share from 28.7 percent to 37.4 percent, according to Kantar. Android meanwhile has lost market share in the US, dropping from 57 percent to 50.2 percent.