Online giant Amazon is set to enter the mobile point-of-sale market as soon as this summer by offering its Kindle device to retailers, according to The Wall Street Journal.

Such a move has been mooted since Amazon purchased Gopago in December, the vendor behind a tablet-based point-of-sale system.

Amazon could package its Kindle for retailers with a credit-card reader, according to sources, in a move that would threaten rivals such as Square.

And the online giant might offer additional services to lure retailers, such as website development and data analysis.

However, Amazon’s plans “remain fluid and the project might be delayed, altered or cancelled”, cautioned the sources.

Amazon’s move follows a similar strategic embrace of physical as well as online payments by PayPal.

And Apple’s iPad is used as an alternative to existing cash registers although the company does not, at least for the moment, supply the underlying payment systems.

Separately, Amazon is also planning a move into P2P money transfer so that users could send cash to one another via their mobile handsets, according to Techcrunch.