TOKYO: Toyota's Prius hybrid - already Japan's highest-selling car - more than doubled its sales in June to claim the top spot for a second month, reflecting government tax breaks and growing popularity of products viewed as environmentally friendly.

The Japan Automobile Dealers Association said Monday that Toyota Motor Corp. sold 22,292 of the Prius cars in June, far more than the 10,915 it sold in May, when a revamped version of the car debuted to clinch the top spot in sales.

June was the third straight month that a gas-electric hybrid topped the Japanese sales charts. The Prius was Japan's No. 2 seller over the first six months of the year, trailing only Honda's Fit compact.

Honda's Insight, a hybrid marketed as a cheaper alternative to the Prius, held the top spot in April but has since slipped, falling to fourth in the June rankings.

The Prius has gotten a boost from a government programme that makes hybrids tax-free, providing an effective discount of about $1,500 for buyers. Japanese consumers have also been increasingly drawn to new products seen as environmentally friendly, which also include solar panels and low-energy TVs.