Telstra, the largest mobile operator in Australia, has written to Vodafone Hutchison Australia threatening legal action over an advertising claim about 4G network speeds made by its smaller rival, according to The Australian.

A new Vodafone advertising campaign contains the claim that it offers “the fastest 4G network in Australia”. The country’s third-placed operator launched its LTE-based service in June.

Telstra has told Vodafone to drop the claim or face legal action, according to the report.

The advertising uses a quote from tech blogger Trevor Long, in which he said of the Vodafone 4G network: “If you’re in the right spot, this network is blistering fast. Easily the fastest 4G network in Australia – if not the world.” Long is happy with Vodafone’s use of the quote.

The operator offers 4G coverage in Sydney, Melbourne, Brisbane, Adelaide, Perth, Wollongong, Gold Coast and Newcastle

Vodafone told the Sydney Morning Herald that it stood by its claims.

The spat over the 4G claims are ironic given that Vodafone has struggled in recent times with network problems. Its difficulties have cost it more than 700,000 subscribers since the start of 2011 and perception of its brand among consumers has suffered as a result. It appears to be looking for redemption among users with its 4G service.

Claims and counterclaims around speed are likely to continue. Network coverage is another area for competition. Telstra is upping the ante with plans to extend coverage to a further 200 regional towns across Australia within the next six months.

The operator’s chief operations officer Brendon Riley said the deployment will take Telstra’s 4G coverage to 85 per cent of the population by Christmas this year, up from 66 per cent at the end of June.