Jubilant TPG and Vodafone say they are ready to take on Telstra and Optus as Australia's third telecoms giant, after the Federal Court ruled the $15 billion merger would not lessen competition and could go ahead.

The decision, which overrules the competition regulator, clears the way for the two firms to form a mega-telco with nationwide fixed-line and mobile infrastructure and  large consumer and enterprise retail operations.