There's a plea from the Christchurch City Council to save the city's water from bottling.

The council is making submissions on Treasury's review of the Overseas Investment Act, in efforts to stop offshore companies taking billions of litres of water for bottling.

Christchurch City Councillor, Vicki Buck, told Mike Hosking it's just one of tools the council's using to combat the issue.

She says they are also exploring putting a water conservation order in place for the city's drinking water to protect it.