Asustek Computer has raised its smartphone shipment target for 2015 to 25 million units, up from the 17 million units set earlier in the year, according to company chairman Jonney Shih.

Asustek shipped 8.5 million smartphones in 2014.

Optimizing the strong sales of its ZenFone-series smartphones, Asustek plans to ship its smartphones to more markets in 2015, Shih said during a product presentation unveiling the company's second-generation ZenFone 2 smartphones.

The ZenFone 2 smartphones are available in four models: ZE551ML (2.3GHz), ZE551ML (1.8GHz), ZE550ML and ZE500CL, with prices ranging between NT$8,900 (US$282) and NT$4,990 unlocked in the Taiwan market.

Both the ZE551ML (2.3GHz) and ZE551ML (1.8GHz) sport a 5.5-inch display and 13-megapixel main camera, priced at NT$8,900 and NT$6,900, respectively. However, the former is powered by an Intel Atom Z3580 CPU and with 4GB RAM, while the latter comes with an Intel Atom Z3560 CPU with 2GB RAM.

The ZE500CL comes with a 5-inch display and 2GB RAM, priced at NT$4,990.