Microsoft has confirmed its flagship Lumia device powered by Windows 10 for phones will be available only when the flagship operating system is ready.

"We remain completely committed and focused on new flagship products. That said, certainly we believe the best time to bring those flagship devices to market is when we have our very latest flagship software experience available. We're focusing our flagship development for slightly later when Windows 10 is available," Neil Broadley, Microsoft's director of phone marketing has confirmed in an interview with The Verge.

The Windows 10 shipment is expected after summer this year, which means the phones with the new operating system are unlikely to arrive until September or October.

It would indeed be a long wait for users, unless other manufacturers such as Samsung and HTC launch their flagships Windows Phone devices ahead of the Windows 10 launch. It will also be a long wait for those waiting to get their hands on the successors of Lumia 920 and Lumia 1020.

At the Mobile World Congress event, Microsoft unveiled two new Lumia budget smartphones- Lumia 640 and Lumia 640 XL, and both are upgradable to Windows 10 which will be available later this year.

Lumia 640 XL with various colour options such as matte cyan, orange, black, matte and glossy white will start rolling out globally this month. The Lumia 640 will be available starting in April in glossy cyan, orange, white and matte black. Both will be available in single-SIM, dual-SIM LTE and dual-SIM 3G variants.

With the affordable Lumia series devices, Microsoft appears to be focusing more on the low-end market segment in a bid to grow its market share. But the latest IDC data suggests the 2014 market share of Windows Phone is only 2.7%, despite the shipment of 34.9 million units.