Plans to bring high-speed rail to the north of England were first put forward by former Conservative chancellor George Osborne in 2014.
A new rail line between Liverpool and Manchester is seen a central piece of the overall Northern Powerhouse rail project, which is aimed at cutting travel times between northern cities and towns as well as boosting the UK economy outside of London.
But expected announcements from the current government were put on ice several times last year due to cost concerns.
Insiders said an extended review process of the project was under way in a bid to avoid mistakes made with HS2, which has been dogged by problems and costly delays.
HS2 is currently tens of billions of pounds over budget and around a decade behind schedule.
Reports state that the now-shortened line between Birmingham and London could cost £81bn.
Accounting for inflation, that would mean at least £100bn will be spent but only 135 miles of railway built.
HS2 Ltd, the company created by the Department for Transport, has accepted it failed to keep overall costs under control and said delivery has not matched what it described as the unrealistic early expectations.
