* Registrations up 17.7 pct y/y in July - monitor SAMAR
* Cost-aware western European consumers boost sales
WARSAW, Aug 5 (Reuters) - Polish new car registrations rose 17.7 percent on the year in July, the most since the start of last year and prompting industry monitor SAMAR to raise its forecast for 2013 passenger car sales by nearly eight percent.
Overall this year sales in Poland, the EU's biggest emerging market but still less than 3 percent of European car sales, are up 1.4 percent compared to last. Adjusted for re-exports they are down 2.4 percent - still far better than most of Europe.
SAMAR, which compiles the data, said that sales of passenger cars and small trucks registered in July rose to 27,957 - the best July since 2008.
It also said the rise was largely due to car traders and ordinary Poles buying imported cars and then reselling them in Germany or other more developed markets, where prices are high enough to generate a solid return on their re-export.
The industry monitor estimated that about a tenth of newly registered cars could be re-exported, mainly to Western Europe. The practice has become steadily more popular due to the zloty currency's weakness in recent years - since 2008 the zloty has lost around a third of its value against the euro.
"Re-export (...) gives a false impression that the (local)market is growing, but in fact it is still in stagnation at best," SAMAR said, adding the 2013 sales of cars would depend on new tax regulation to be implemented by the finance ministry.
The July rise in registrations led SAMAR to raise its 2013 passenger car sales forecast by 7.7 percent to 280,000 units.
Last month data showed that the European car market was still in doldrums with first-half sales hitting their lowest level in two decades, suggesting no let up for an industry battered by overcapacity and weak demand.