Tech giant Google will have to open its Android smartphone operating system to rival app stores, a US judge has ordered.

A California jury decided on Monday that Google wields illegal monopoly through its Android Play store.

This is yet another setback for the company after a different federal judge in August found that Google's search engine was also an illegal monopoly.

What does the verdict mean?

According to the order, Google cannot prohibit the use of in-app payment methods for three years and must allow users to download competing third-party Android app stores.

The order also restricts Google from making payments to smartphone makers to preinstall its app store, as well as from sharing revenue generated from the Play store with other app distributors.

The judge has also ordered the creation of a three-person technical committee to oversee the implementation of the changes and resolve any disputes that may arise.

The order was effective starting November 1, the judge said, with some provisions given until July 1 to be implemented.

How did Google react? 

Google is appealing the order. It argued that the changes which the judge ruled must be implemented would "cause a range of unintended consequences that will harm American consumers, developers and device makers." 

"We look forward to continuing to make our case on appeal, and we will keep advocating for what is best for developers, device manufacturers and the billions of Android users around the world," said Lee-Anne Mulholland, the company's regulatory affairs vice president.

Phones using the Android software constitute some 70% of the world's smartphone market.

Smartphone makers can install the Android app for free under the condition that the Play app store remains on the home page, and that other Google apps are pre-installed.

ftm/rmt (AFP, Reuters)