File photo of a local sportswear brand ANTA in China.

HONG KONG - GPS sport watches, compression leggings and hydration packs are the new must-haves for wealthy Chinese, pumping up the multi-billion dollar sportswear industry at a time when China's elite are reining in spending on more traditional luxury brands.

Extreme sports apparel and expensive active wear is in vogue thanks in part to government promotion of sport ahead of the 2022 Winter Olympics in Beijing, and the purchase of the Ironman brand by China's richest tycoon last year.

The market is also forecast to grow with the government's decision to relax its one-child policy after 36 years, and companies like US-listed Under Armour and Canada's Lululemon Athletica Inc are lining up to cash in.

"It is huge - that wellness and healthy lifestyle opportunity in the whole of China," said Colin Grant, chief executive of the Hong Kong-headquartered Pure Group, an operator of gyms, yoga, retail and nutrition businesses across Asia.

"Luxury has its challenges but active wear is a bright spot in the industry. Some people wear it to weddings in China."