MORE Singapore-listed players fighting for a slice - even crumbs - of the lucrative water treatment business pie in China have created a "bubble" amid intensified competition and squeezed margins for Chinese water projects.

In the latest quarterly results, a handful of such Singapore-listed companies suffering lower revenues and earnings cited factors that include fierce competition, higher financing costs and rising foreign worker wages.

Foreign companies have been piling into the Chinese water market after the country vowed to invest 430 billion yuan (S$87.3 billion) in the sector over the 12th five-year plan period from 2011 to 2015 - 17 per cent more than the previous period. Of this, two-fifths are earmarked for wastewater and sludge treatment facilities.