Speaking to Fairfax Media for his first sit-down interview since taking over Optus in October 2014, Mr Lew said his vision was to turn it into Australia's fastest growing mobile-led multimedia company over the next three years – a move he acknowledged would need substantial spending to achieve.

The move will likely worry Telstra, whose dominance of the mobile market has been a key driver of its profit and revenue growth over the past five years as customers slow their use of traditional telco services like home phone lines.

"We want to grow Optus and take back the market share," Lew said. "The network construction is a big, big part of what we want to do.

"We will get [our mobile network] to being the best."

Optus is set to spend $1.2 billion on both its fixed-line and mobile networks in financial year 2015 while Telstra budgeted $1 billion for the expansion and maintenance of its mobile network alone over the same period.

In 2014 the top three telcos alone generated almost $18 billion in revenue from their mobile divisions.

Telstra has consistently grown its mobile subscriber base and now has 16 million customers compared to Optus' 9.4 million and around 5 million at Vodafone Hutchison Australia.

Mr Lew said financial regulations prevented him from providing a firm guidance on how much the telco would spend in financial year 2016, but that the market would appreciate Optus' resolve when the financial results were released in May 2015.

"If we want to win in this marketplace we will have to walk the talk [and] when we give the specific guidance it'll be proof to the market that we are able to execute and deliver on this promise," he said. "What I want to build is the depth of coverage, the speed of coverage. And that's step one to being the best video delivery service in Australia."

He said becoming the leading player within three years would help attract more customers. This would in turn encourage global media companies like Netflix and HBO to partner with Optus as content providers sold their products directly to consumers.

Mr Lew's comments echo those made by Optus' recently departed head of network, Vic McClelland, who told Fairfax Media last year the company aimed to catch up with Telstra's mobile network by 2016.

The company aims to reach 90 per cent of Australians with 4G services by March 2015 while Mr McClelland said the ultimate goal was to reach 98.5 per cent by 2016.

"If Vic said it then you can assume we've had internal discussions about that," he said. "Since SingTel bought Optus it has invested more than [$14 billion] into Australia.

"If we truly believe the world is going to go to mobile internet we need to make sure our infrastructure goes where people go."

But Telstra understand the importance of its mobile network and is unlikely to let Optus lead without a fight. In 2014 its retail group executive Gordon Ballantyne said the telco would "respond accordingly" if its rivals tried to match its network superiority.

Telstra is also keen to tout its advantage in spectrum, which is the electronic airspace used by broadcast technologies like mobile phones.

Telstra this month got access to the $1.3 billion in 700MHz spectrum it bought at auction in 2013, which is best suited at sending signals deep into buildings and over longer distances. By comparison, Optus bought $649 million of 700MHz at the same event.

But Optus' Mr Lew claimed the sheer size of his 2300MHz holdings, which are less suited for penetrating buildings, would deliver download speeds in the hundreds of megabits per second in crowded areas like shopping centres and sporting arenas.

Nomura research analyst Sachin Gupta said that while it was entirely possible for Optus to hit its stated aim, the move would require substantial increases in spending.

"There's still a fair bit of an investment gap between Telstra and Optus," he said. "SingTel isn't averse to spending money but it's had to pick its battles and so far they've invested more in other regional associates.

"In Australia they have found it challenging but obviously with this new management team they'll have to address the network issues the company has had on the mobile side."