Secretary for Environment and Ecology Tse Chin-wan said on Saturday a move to redraw the boundaries of protected wetland areas and their buffer zones is aimed at enhancing conservation rather than freeing up land for development.

Speaking to reporters after an RTHK programme, the minister said the current strategy for designating conservation areas in the territory had led to many plots being deserted rather than conserved.

"Of course, that has served a purpose of conservation to some extent. But actually we have also seen that because of a lack of management, a lack of attention, the conservation value of that piece of land can deteriorate," Tse said, pointing to Nam Sang Wai in Yuen Long, where many fish ponds there have dried up.

He said officials are now conducting a study to identify lands that will form the three wetland conservation parks proposed as part of the Northern Metropolis development plan.

Tse stressed that the move would help support biodiversity.

"We should identify those areas with high conservation value, and then, we should try to recover the adjacent lands which are abandoned, which have been deteriorated, or lost their conservation value...so that we can form a contiguous, bigger piece of land for conservation," Tse said.

"It's not that we are redrawing it for purpose of development, but rather, we are going to redraw the boundary because of the new identified and planned wetland parks."

Separately, the environment chief said he noted calls to impose a higher plastic bag levy of HK$2, instead of the government's proposed increase from the current HK$0.5 to HK$1.

Lawmaker Tony Tse – who represents the architectural, surveying, planning and landscape sector – said earlier he believed a HK$2 levy would be more effective.

The minister said the government would stick to its proposal of charging HK$1 per bag, but he respects the suggestions of a higher levy.