Amazon has revealed plans to introduce its Appstore for Android to almost 200 countries in the coming months, as it seeks to boost digital content revenue and take on rivals such as Apple and Google.

Developers are being invited to submit apps for distribution in countries including Australia, Brazil, Canada, South Korea and even Papua New Guinea and the Vatican City.

Separately, the retailer has launched 50+ Active and Healthy Living store on its site.

The store targets customers aged 50 and over.