The company is asking suppliers to manufacture 85 million to 90 million units of two new models with 4.7-inch and 5.5-inch displays, expected to be called iPhone 6s and iPhone 6s Plus.
The new phones are also expected to feature Force Touch technology which can distinguish between a light tap and deep press, people familiar with the matter told the Journal.
The information about orders came from Apple's suppliers, the paper added.
The screen sizes are the same as in the iPhone 6 andiPhone 6 Plus. Apple is also expected to maintain the screen resolution, the Journal said.
Some component suppliers started manufacturing parts for the new iPhones in large quantity earlier this month, the newspaper reported.
Hon Hai, Apple's primary assembler also known as Foxconn, has been recruiting workers at its main iPhone production base in Zhengzhou, north-central China, anticipating mass production to begin next month, the journal reported.
Apple could not immediately be reached for comment.
Apple's shares were down 1.8 percent at $123.50 in afternoon trading on the Nasdaq.
© Thomson Reuters 2015