Councillors approved a flood-risk management plan, which predicts 4450 properties will be at risk of permanent inundation by 2100.

The plan is based on worst-case scenarios of rising sea levels and flood.

It said the lake was expected to have an ‘‘average lake level’’ of one metre by 2100, rising from its average level of 0.1 metres above sea level now.

A draft of the plan, released last October, prompted Belmont businessman Jeff McCloy to threaten legal action against councillors for devaluing and restricting waterfront properties.

Only one councillor spoke on the matter at last night’s meeting.

Cr Hannah Gissane said the council was ‘‘doing a great job in this area’’.

The Newcastle Herald reported on Friday that the council was pushing for more power and money to deal with climate change.

The push was revealed in a submission to a Productivity Commission inquiry into ‘‘barriers to effective climate change adaptation’’.

The flood plan said the council aimed to establish a criteria for when inundated land became unsuitable for use.

Additionally, it would review land use to determine suitable development types for floodprone land and the possible need for housing to retreat from the shore.

It would develop financial models to ‘‘prepare for future costs of possible protection works, infrastructure upgrades and relocations’’.

In creating its flood plan, the council used NSW government data that predicts sea levels and the lake will rise by 0.9 metres by 2100 because of climate change.

The council calculated that the lake would rise to 2.32 metres in 2100 if a one-in-100 year flood occurred.