Vodafone Hutchison Australia's revenue plummeted 12 per cent in the six months before the merger with TPG Telecom in late June, as the COVID-19 fallout and pre-existing problems caused the telco to lose mobile customers.

In the merged company's first set of half-year results, TPG Telecom reported a six month revenue of $1.5 billion, down 11 per cent on the previous period. Earnings before interest, tax, depreciation and amortisation fell 9 per cent to $531 million.