Japanese mobile phone operator NTT DoCoMo is developing an Android-based smartphone, according to a Nikkei business daily report.

To be produced in conjunction with South Korean partner KTF, the phone is said to be due to launch next year, although this has not been officially confirmed by the companies.

DoCoMo owns 10% of KTF and the two companies have been jointly procuring handsets in order to cut costs.

The report suggests that the operator will offer the as yet unnamed handset for around 20% lower than existing smartphones, passing on the savings from using Google's free Android software.

No Japanese or South Korean carriers yet offer an Android phone, with T-Mobile the only operator to have launched a device, the HTC-made T-Mobile G1 with Google.