Vodafone lost 375,000 customers in the first six months of this year as customers abandoned the telecommunications company because of poor mobile reception.

A telecommunications analyst said Vodafone had a "short window of opportunity" to improve its network or face further defections.

Parent company Hutchison Telecommunications Australia will book a $96 million downturn with a loss of $78.2 million for the six months ending June 30, compared with a profit of $17.8 million for the same period last year.

It attributed the loss to network and customer service issues.

"The decline in Hutchison Telecom's profit was driven by a $15.6 million decrease in interest income following the repayment of shareholder loans by VHA during 2010, and a decrease in VHA profitability following the network and customer service issues experienced by some customers in late 2010 and early this year," said chief executive officer Nigel Dews.