The company behind current smartphone craze "Pokémon Go" has expanded on the reasons behind recent changes to the game and why it shut off access for several popular fan-made apps.

Since Android and iOS app "Pokémon Go" launched early in July, it has attracted worldwide attention.

Its developer, Niantic, spun-off from Google late in 2015, had succeeded in creating a far fluffier version of its augmented reality game "Ingress" which, in part, could explain how pedestrians used mapping software and local knowledge to get from one place to another.

"Pokémon Go" takes a mobile phone's camera, internet data connection, and global positioning gadgetry, and combines them for a global game of hide-and-seek involving small, collectible creatures at the heart of a 20-year-old video game, cartoon, and merchandising franchise.

Pokémon are graded according to rarity, and their appearances are centrally co-ordinated, which is why phones need a data connection to know when and where to show them, while an on-board location service means the phone knows how near or far they are.

But such was the demand for "Pokémon Go" that fan communities immediately started looking for ways to help them find and file these virtual creatures.

One of those ways involved unofficial, online maps that showed where all Pokémon were.

That way, enthusiastic players could head straight for a specific location, rather than meander about according to vaguer hints provided by the app.

But those fan-made maps, as well as other, less desirable encroachments, had a significant impact on how well Niantic was able to support the game as a whole.

"We wanted to shed some more light on [...] why these seemingly innocuous sites and apps actually hurt our ability to deliver the game to new and existing players," company founder John Hanke explained in an August 4 blog post.

An accompanying graph appeared to show that strain on the game's data servers fell by two-thirds after Niantic blocked unauthorized access on August 1.

That made it possible to provide official support for "Pokémon Go" in Latin America, including in Brazil, Hanke said.

The block also meant Niantic could prevent cheaters and even those looking to "break into systems, hijack social media accounts, and even bring down the service."

"We don't expect these attempts to stop. But we do want you to understand why we have taken the steps we have and why we will continue to take steps to maintain the stability and integrity of the game."