Struggling smartphone maker HTC plans to slash around a quarter of its global workforce through job cuts at its manufacturing unit in Taiwan, as the company continues to battle dwindling sales.

HTC said it would cut 1,500 jobs in its manufacturing unit in Taiwan. This represents about a quarter of the 6,450 staff it employed globally as of June.

"Today HTC announces plan to optimize the manufacturing organizations in Taiwan ... This plan will allow more effective and flexible resource management going forward," HTC said.

The layoffs will be completed by the end of September. The move is also part of a broader plan that brings HTC's smartphone and VR businesses under common leadership in each region.

Late last year, HTC shifted around 2,000 staff, mainly handset engineers, to Alphabet's Google, as part of a $1.1 billion deal.