Apple’s last-month released iPhone 3GS has hit the markets, of the 18 countries where it is currently available, with a bang – what with the supplies of the new smartphone already falling short of the unexpectedly high demand!

The current demand-supply imbalance of the new iPhone 3GS would need to be addressed soon, more so with Apple intending to launch the smartphone in almost 80 more countries this summer.

Talking about the ‘shortage’ of the new iPhone supply – as well as that of Apple’s MacBook Pro notebooks – Apple said on Tuesday that it might be some weeks before the shortages are dealt with. The June quarter results show that though Mac sales were noteworthy, iPhone sales were astounding!

Beating analysts’ estimates, the sales of the iPhones touched nearly 5.2 million units, including the sales figures of Apple’s reduced-cost $99 iPhone 3G.

Acknowledging the constraint in the supply of the iPhone 3GS, Apple executives said during a conference call that the surge in the demand of the smartphone had actually surprised the Cupertino, California-based company.

Commenting on the iPhone 3GS’ current supply situation, Apple’s Chief Operating Officer, Tim Cook, said that supply and demand of the smartphone is not likely to be balanced in the short-term. About new roll outs, Cook said most countries that sell the 3G will be selling a 3GS by the end of this quarter.