The phones also feature improved charging times and wireless charging technology.
Samsung says both devices can fully charge through wired fast charging in approximately 90 minutes, and fully charge through Samsung's newest wireless charger in approximately 120 minutes.
For selfie fans, Samsung has also improved the front cameras to 5 megapixels rather than the previous 3.7.
Both phones sport aluminium frames and glass backs rather than plastic.
The Galaxy Note 5 also includes a stylus to take hand-written notes, edit images and annotate PDF documents.
They will both be available in New Zealand from August 28, and pre-ordering is available.
Samsung also said its Samsung Pay mobile payment service will debut in its home country of South Korea on August 20. Testing in the U.S will begin August 25, with a formal launch on September 28.
The timing reflects a shift in fortunes for a company that pioneered jumbo phones with the original Note in 2011. Now, Samsung needs to beat Apple to the punch, or risk seeing its products drowned out by all the attention on the iPhone, IDC analyst Ramon Llamas said.
Although there's competition from Apple Pay and Google's upcoming Android Pay, Samsung is hoping its payments system will catch on with the inclusion of a technology that mimics the old-school, magnetic signals from credit-card swipes. That allows it to work with a wider range of merchants, though it still won't work everywhere cards are accepted.
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Samsung has also teased an upcoming smartwatch, the Gear S2, in the US. It will have a round face, rather than the rectangular design in Apple Watch and previous Samsung watches. A video from Samsung suggests snazzy graphics to rival Apple Watch. More details will come at the IFA tech show in Berlin next month.
Despite the Samsung's advances in technology and design, sales have fallen below expectations, as Apple continues to dominate the high-end market. Rival Android phone makers have also been able to offer decent cameras, displays and speeds for less money than Samsung phones.
Although it's still the leading smartphone maker, Samsung has reported five consecutive quarters of profit decline.
"There's an urgency to show that Samsung can still stand up to the challenge that is Apple and everybody else out there," Llamas said. "For a while, Samsung was the 'be all and end all' of Android devices. Now, it's a different market."
- Additional reporting: AP