Efforts to detect and remove malicious apps from the Google Play Store have improved, Google said, after it increased the number of rejected app submissions by more than 50% in 2018.

The tech giant, which runs the Google Play Store for its Android operating system on smartphones and tablets, claims it now scans more than 50 billion apps on user devices daily to ensure they are not behaving harmfully.

In 2018, new policies were introduced that helped drive the number of rejected app submissions to an increase of over 55%, while app suspensions went up by 66%.

Eight in 10 severe policy violations are carried out by repeat offenders, Google claimed, but said its account-matching technologies have been enhanced along with human reviewers to drive out repeat offenders, who create new developer accounts when banned or buy developer accounts on the black market.

The company has recruited more staff to steer its crackdown, including product managers, engineers, policy experts and operations leaders.

Google pledged to take further steps to protect user privacy with the introduction of new policies for device permissions and user data in 2019.

“Despite our enhanced and added layers of defence against bad apps, we know bad actors will continue to try to evade our systems by changing their tactics and cloaking bad behaviours,” said Andrew Ahn, product manager for Google Play.

“We will continue to enhance our capabilities to counter such adversarial behaviour, and work relentlessly to provide our users with a secure and safe app store.”