Auction of 4G spectrum is to be investigated on behalf of taxpayers after revenues failed to meet expectations.
The recent 4G auction is to be scrutinised by the National Audit Office (NAO) to ensure the public-funded sale delivered taxpayers "value for money".
Earlier this year, Ofcom held a spectrum auction in which mobile providers were invited to bid for the mobile broadband airwaves required to launch 'superfast' 4G networks.
Although the sale raised £2.4billion for the UK economy, revenue was still over £1billion short of government forecasts.
Helen Goodman, shadow communications minister, told the Guardian it was "entirely right" that the NAO was launching its investigation.
She said: "Serious questions must be answered as to why the Conservative-led government ended up £1billion short of the estimate George Osborne had provided just months earlier.
"When the 3G auction took place, Labour ensured that maximising revenue was an objective. The conservative-led government didn't do the same for the 4G auction, which I believe was a serious mistake."
4G is dubbed the 'next generation' of mobile broadband, delivering speeds much faster than the current 3G airwaves used by most people accessing the internet on the move.
At present, EE is the UK's only major 4G mobile network, but O2, Vodafone and Three are all expected to have 4G services up and running by the end of this year.
The UK's 3G spectrum auction, held way back in 2000, raised a staggering £22billion.