Australia's largest telecom company Telstra will soon be ready to give customers the next-generation of ultra-high speed mobile internet, known as 5G, its CEO said on Thursday.

Mobile is the "engine room" of Telstra's business and it will be a critical part of the future, Andrew Penn told CNBC's "Street Signs."

"We have had more than 200 sites rolled out on 5G now," he said. "We'll be one of the first global operators to actually put 5G in the hands of our customers in the coming months when handsets are available."

Penn's remarks came after Telstra released its half year results for financial year 2019 on Thursday morning.

Net profit after tax was down 27.4 percent on-year to 1.2 billion Australian dollars (approximately $854 million) in line with expectations. The company said its financial results were affected by a partially-completed fiber network, which is owned by the government. Essentially, Telstra has to pay before it can connect to that network to provide broadband internet to its customers.

"We have a structural change in the industry where, essentially, a significant proportion of our business is being aggressively transferred to this new entity," Penn said, adding that it "basically takes away about a third-to-half of our earnings in a lot of our activity."