Australia's AGL Energy has made a fresh A$3.02 billion ($2.10 billion) takeover approach to telecoms company Vocus Group Ltd, after a rival suitor withdrew its offer last week.

AGL said on Tuesday it has been granted exclusive access to conduct due diligence on Australia's fourth largest internet provider for four weeks, after submitting a non-binding, indicative acquisition proposal at A$4.85 a share.

The all-cash offer is below the A$3.3 billion buyout proposal made by Swedish private equity firm EQT Infrastructure, which was the fourth suitor to drop a bid for the telecoms company in the last two years.

"AGL's interest in Vocus is consistent with AGL's strategy to meet the needs of increasingly connected customers as energy and data value streams converge and the traditional energy sector transforms," the company said in a statement.

Vocus Managing Director and Chief Executive Officer Kevin Russell said "there is a clear market opportunity for Vocus, which is generating significant interest in our business and our assets".

AGL walked away from its previous offer when it could not agree on due diligence terms.

AGL, which is seeking growth outside its slow-and-steady electricity retailing business, is looking to bundle data and energy services, as well as enable efficient power use as more homes install smart meters, solar panels and batteries for energy storage.

Sydney-based Vocus saw similar approaches in 2017 when U.S. buyout firm KKR & Co Inc and Affinity Equity Partners made, then abandoned, their own plays for the then struggling telco.