The Turnbull government is hinting that the rapidly declining cost of renewable energy is undermining the case for further clean-energy subsidies, as it maintains it will make a decision on a clean energy target in coming months.

In a speech to the Australian Financial Review's National Energy Summit in Sydney on Monday, Energy Minister Josh Frydenberg has emphasised the "declining cost curve" for wind, solar and renewables storage.

"Globally in the past seven years, the cost of wind-powered generation has more than halved. Domestically, solar PV costs have dropped more than 50 per cent," he said.

"By 2020, costs of battery technologies are expected to fall 40 to 60 per cent and over 70 per cent to 2030.