SINGAPORE - Singapore will be looking underground for new places to store its water infrastructure, said Minister for Environment and Water Resources Vivian Balakrishnan in Parliament on Wednesday.

National water agency PUB is also calling a tender to study the feasibility of using underground space, such as rock caverns, for the redevelopment of its Kranji water reclamation plant and Newater Factory.

The plant and factory are expected to be redeveloped and expanded around the year 2030, as part of the integrated used water system consisting of the Changi, Tuas and Kranji water reclamation plants in east, west and north Singapore respectively.

"Currently, Singapore's water reclamation plants are built on surface land. With a limited land area of about 718 sq km, Singapore is continuously challenged to come up with innovate and practical solutions to create new spaces," said PUB.

"The relocation of utilities infrastructure underground has the potential to free up surface land for other uses, and create a more pleasant living environment for people to live, work and play above ground," it added.

The feasibility study is expected to be completed by 2016, and will look at the challenges of constructing and operating a plant in an underground cavern. These include the need for back-up systems for power, odour control, air ventilation and other mechanical systems.

Designs to cope with potential floods or fires will also need to be put in place.