M.G. Siegler noted in a blog post late Monday that "multiple sources" have told him the launch of the application is imminent.
"I believe it has already been submitted to Apple for review. If it gets approved, it should be out soon," he wrote, adding that he believes it will get approved.
Siegler went on to note that tipsters have said the app looks "pretty fantasticperhaps even surprisingly so." A key feature of the app is expected to be the addition of push notifications for the popular email service. Other likely feature additions include Priority Inbox and one-click starring of messages, according to him.
The author also speculated that upcoming Gmail features such as "contact icons, better threading, deep searching functionality," and even Google+ integration could make their way into the iOS application.
Despite the arrival of Apple's App Store in 2008, Google has preferred to use a Web interface for Gmail on iOS. Apple's native Mail app on iOS has included support for Gmail accounts for years, though it lacks a number of the features that Google offers via the Web app.
Numerous reasons have been put forth for the delay in a Gmail app. Originally, some suggested that Apple was blocking third-party mail apps to avoid confusion with its own Mail program. Google's tendency to favor Web apps for its services. More recently, friction between Apple and Google over the Android operating system has been cited as another cause of the delay.
According to a recently released biography, late Apple co-founder Steve Jobs vowed to "destroy Android" after handset maker HTC released an Android smartphone that he felt stole his company's innovations.
"I don't want your money. If you offer me $5 billion, I won't want it. I've got plenty of money. I want you to stop using our ideas in Android, that's all I want," Jobs reportedly told Schmidt during a meeting in 2010.