Softbank Corp. said Tuesday its agreement last October to acquire Sprint Nextel Corp. is pretty much a done deal, as the mobile service giant responded to a new counter bid from U.S. satellite television provider Dish Network Corp.

"The Softbank-Sprint transaction is in the advanced stages of receiving the necessary approvals and we expect to consummate the transaction on July 1, 2013, with the terms already agreed," Softbank said in a press release.

The third-largest mobile phone service provider in Japan also said the Dish proposal is highly conditional and it "believes that the agreed terms of our transaction with Sprint offer Sprint shareholders superior short- and long-term benefits."

Dish on Monday announced a $25.5 billion bid to acquire Sprint, against the $20.1 billion bid for 70 percent of Sprint announced by Softbank in October.

Softbank has said its deal would create the world's third-largest cellphone carrier by sales and also be one of the largest overseas acquisitions by a Japanese firm.