Last month Cantor Fitzgerald analyst Brian White claimed that the 4.7-inch iPhone will be released in September, while the 5.5-inch phablet version could arrive the next month.
A report by Bloomberg announced that the production of the two iPhone models is expected to start in July and that both models could be presented at the same time in September.
The report added that production of the 5.5-inch iPhone could be more difficult due to a new type of display with tapered edges.
Speculation about a September 19 launch further arose when Chinese Internet company Tencent reported about the date.
The publication also wrote that the two iPhones will be available in two storage versions: a 32 GB version priced at 5288 yuan or about $850, and a 64 GB model that costs 6,288 yuan, or $1,008.
The first rumor surfaced when German carrier Deutsche Telekom informed customers about a September 19 release date for the smartphone.
Earlier this week sources cited by China.com claimed that the 4.7-inch iPhone 6 and the 5.5-inch model will be unveiled on September 25, adding that the phablet iPhone will be named the iPhone Air.
Now a new report by MacRumors claims that the September release date was confirmed by a reliable source.
Mass shipments of the device from China to the US will reportedly take place in the last two weeks of August and the iPhone 6 could be unveiled in the first or second week of September.
The smatphone will arrive on the market later in the month most likely on a Friday.