BlackBerry maker RIM is offering customers in India a rather significant incentive as it looks to encourage sales of its struggling PlayBook tablet.

A new promotion from the Canadian giant will see customers that purchase a PlayBook also given a free phone – the BlackBerry Curve 8520 – in a move to push sales of the PlayBook in India’s increasingly crowded tablet space. The PlayBook competes with Apple’s iPad, a range of Android-based devices including the Galaxy Tab and Motorola Xoom and a host of low-cost tabletd.

The offer is open across all versions of the device – the 16GB, 32GB and 64GB models – and will run during India’s Diwali period, the festival of light celebration, beginning today until November 30.

It remains to be seen if RIM will adopt a similar approach to marketing the PlayBook in other Asian markets, particularly Southeast Asia where its BlackBerry smartphones are hugely popular and such a deal could have increased significance.

The move could also be partially motivated by the series of recently outages, which were particularly received particularly badly in India. The country’s mobile market has huge potential, as was recently demonstrated when Japanese operator SoftBank launched a joint venture with carrier Bharti focused on developing mobile Internet in the country.

RIM recently called rumours that the tablet series was being discontinued “pure fiction”, however its sluggish performance – which has seen shipments dip below RIM’s own predictions – has had repercussions for one of its manufacturers in Taiwan who was forced lay-off 1,000 workers after reduced orders.