Shares in struggling smartphone maker HTC tumbled to their lowest level in more than a decade Monday after the company forecast its biggest-ever quarterly loss owing to weaker-than-expected demand from the Chinese mainland market.

Taiwan-based HTC revised its second-quarter guidance late on Friday, with sales predicted to slide to NT$33 billion-NT$36 billion ($1.06 billion-$1.16 billion), down sharply from the previous forecast range of NT$46 billion-NT$51 billion.

The earlier second-quarter forecast, made in April, would have marked an increase from first quarter sales of NT$41.52 billion.

HTC also wrote off NT$2.9 billion in idle assets and prepaid expenses, it announced on Friday.

Overall, the company forecast a record quarterly loss of up to NT$9.94 per share, compared with a minor profit when the previous guidance was released in April. 

"The change for revenue outlook is due to slower demand for high-end Android devices, and weaker-than-forecast sales in the mainland market," the company said in a statement on its website.

As a result, Taiwan-listed HTC shares on Monday fell by the daily limit of 10 percent to NT$83.60, their lowest level since it got listed in 2002.

Analysts said the firm faces competition from low-cost rivals from the mainland along with tech giants Apple and Samsung.

"As highlighted earlier, HTC's high-end flagships (M9, M9+) are visibly inferior to the competition, not just to Apple and Samsung, but also to Huawei and Xiaomi to some extent," Jeff Pu of Yuanta Securities Investment Consulting said in a note to clients.

HTC reported net profit of NT$360 million in the three months to March, lower than the NT$470 million it recorded in the previous quarter but up from a loss of NT$1.88 billion in the same period a year ago.

The company suffered its first ever net loss in the third quarter of 2013, as it slipped out of the world's top 10 mobile phone vendors.