Apple has announced it is going to permanently change iPhone settings to block a method used by police and intelligence agencies to access devices.

The technology giant says it wants to protect all customers, especially those in countries where the phones are stolen a lot.

The change will see a phone's charging and data port effectively disabled when a phone has not been unlocked for more than a hour.

Under the change, entering the correct password for the device will be necessary to enable the port's data transfer functions again.

According to the New York Times, the change is targeting an unlocking process which involves "connecting another device running special software to the port".

In a statement, Apple said: "We’re constantly strengthening the security protections in every Apple product to help customers defend against hackers, identity thieves and intrusions into their personal data.

"We have the greatest respect for law enforcement, and we don’t design our security improvements to frustrate their efforts to do their jobs."

A number of companies offer law enforcement groups services to unlock iPhones, including Israel-based company Cellebrite and US firm Grayshift.

Apple became involved in a legal dispute with the FBI in 2016 when the company refused to unlock a phone used by a suspect in the San Bernardino mass shooting.

At the time, Apple argued that doing so would 'create a backdoor' and cause serious privacy concerns for iPhone users, saying: "We fear that this demand would undermine the very freedoms and liberty [the US] government is meant to protect."

The FBI request was ultimately dropped when a third-party offered a service to unlock the phone.