Japan's biggest mobile phone operator NTT DoCoMo Inc's group operating profit likely fell 16 percent to about 250 billion yen ($2.68 billion) in the April-June quarter as the year-earlier boost from reduced sales costs wore off, the Nikkei business daily said.

Quarterly sales likely dropped 2 percent to around 1.15 trillion yen and handset unit sales may have dropped, the paper said, adding that average revenue per user also appears to have fallen.

However, DoCoMo added a net 112,400 contracts in June alone -- just 500 fewer than Softbank Corp, the paper said, without citing any sources.

For the full year ending next March, DoCoMo is expected to maintain its forecast of a 1 percent drop in sales to 4.38 trillion yen and a nearly flat operating profit of 830 billion yen, the Nikkei said.

($1=93.38 Yen)

(Reporting by Shailesh Kuber in Bangalore; Editing by Deepak Kannan)