A contentious plan to split AGL Energy into two is at risk of heading for the scrapheap following the latest offensive from tech billionaire Mike Cannon-Brookes, despite support through a $2 billion deal with US-based giant Global Infrastructure Partners.

Mr Cannon-Brookes and AGL chief executive Graeme Hunt traded verbal blows on Tuesday after it was confirmed the Atlassian co-founder had secured rights over almost 11.3 per cent of the country’s biggest generator of electricity with a view to vote down the demerger next month.