The Government's plans for the HS2 high-speed rail project must not lead to less investment in the rest of the network, a transport campaign group says.
Budgets could be cut on other rail schemes while the Government concentrates on HS2 whose first stage will run from London to Birmingham, the Campaign for Better Transport (CBT) said.
Its comments came ahead of a Government launch next week of consultation on HS2 which could cost around £33 billion if the section north of Birmingham goes ahead.
CBT director Richard Hebditch said high speed rail (HSR) could offer “an opportunity to improve transport in the UK and provide greener choices for long-distance travel”.
“But the danger is that the Government is so focused on just getting plans through in the face of local opposition that it ignores the need for it to be part of improving the whole network.
“We're very worried that ministers will need to cut budgets elsewhere to pay for HSR. That could mean even steeper fare rises and cuts in local rail services in order to pay for it.”
Hebditch said the best way for rail to offer a greener alternative is to electrify much more of the network but plans for electrification could be put back as HSR eats up all the funding.
Meanwhile, 69 top businessmen, including CBI director-general John Cridland and former British Airways chief executive Willie Walsh, have given their backing for HS2.
In a letter to the Financial Times, the top bosses, including chambers of commerce leaders, said HSR would boost the British economy, create new jobs and improve growth prospects.
"We believe the Government is right to develop a new high-speed rail line linking the major cities in the Midlands, the north of England and London. An HSR link will give the economy a much-needed boost, particularly in the north and Midlands.
"Not only will an HSR link create much-needed capacity and reduce journey times, it will also improve connections between airports, help current commuter services, and free up space on existing lines to carry more freight. All this will provide significant help for British business and attract additional new investment," the letter read.
However, HS2 is bitterly opposed by a number of residents' groups and some Tory MPs, while there is also doubt as to whether the London-Birmingham first stage can possibly be started in 2015 as planned.
It is thought that the Government's HS2 consultation - likely to be launched on Monday - will show that around 4,860 homes will experience extra noise as a result of the line which will run through beauty spots.
It is also understood that only 10 properties will suffer from high noise levels and that only another 150 will need noise insulation.
Stop HS2 group chairman Lizzy Williams said the Government was intending to spend £215 million in addressing concerns about noise.
She added talk of noise levels was "a distraction tactic" ahead of next week's announcement.
"We want to see the project scrapped altogether.
"To continue spending on this project when essential services are being cut when there is simply no business case or no environmental case is quite frankly immoral,” Williams said.
Transport Secretary Philip Hammond said all other major economies were pressing ahead with “ambitious HSR plans - Britain must not be left behind”.
"However, we have been quite clear that investing in HSR isn't something we will do instead of improving commuter services, but in addition.
"We will be spending billions of pounds over the coming years to improve commuter services and, in the long run, HSR will also help relieve pressure on the existing rail network.
“Building the initial London-Birmingham high-speed line is expected to require average funding of around £2 billion per year, broadly similar to the level of annual expenditure on London's current Crossrail project,” Hammond said.