Vodafone has reported a half year pre-tax profit of £1.5 billion as it announced that trading in Europe remained “very tough at present”.
Mr Colao said the emerging markets businesses were doing well thanks to the growth of smartphone usage.
He said he hoped for a shift in regulation to support industry investment and consolidation.
Mr Colao said mature markets were “challenging”, but that focusing on cost efficiency was helping.
The figure marks a big fall from its £3.9 billion half-year pre-tax profit in 2012.
Vodafone, the world’s second largest mobile operator said it plans to spend £7 billion on improving its networks by March 2016.
The move follows Vodafone’s deal in September to sell its US business to Verizon Communications for £81.2 billion.
The US arm made up 45% of Vodafone’s business, and the deal marked one of the largest to date in corporate history.
As part of its growth plan, “Project Spring”, the introduction of 4G networks, will be accelerated and investment for laying fibre optic cables increased, to allow Vodafone to offer faster broadband to its customers.