The government has been warned that HS2 needs a "major rethink" and northern cities like Leeds are being short-changed by the high speed rail plans.
The warning comes from the House of Lords Economic Affairs Committee report, released on Thursday.
In the report, the HS2 proposals were criticised for "short-changing" northern cities in favour of London commuters.
Lord Forsyth of Drumlean, Chairman of the Economic Affairs Committee, said that rail infrastructure in the north should be the government's priority, not improving north-south links, which are already good.
Lord Forsyth said: "Commuter services in the north of England are badly overcrowded and reliant on ageing trains.
"Rail connections between northern cities are poor.
"As the Committee suggested in its 2015 report, rail infrastructure in the north should be the Government’s priority for investment, rather than improving north-south links which are already good.
"The north is being short-changed by the Government’s present plans, especially as construction on HS2 is starting in the south. Any overcrowding relief from HS2 will mainly benefit London commuters."
He added that the plans for the Northern Powerhouse Rail should be integrated with the plans for the northern section of HS2, and funding for the project ringfenced.
Phase 1 of HS2 is due to open between London and Birmingham in 2026, before being extended to Manchester and Leeds.
The committee criticised that decision stating that construction should have begun in the north.
The report also raised several other concerns.
It raised "serious reservations" about the analysis methods used by HS2 to determine where the rail line would be value for money.
The report also added that the peers were "far from convinced" that the HS2 railway could be built within its £55.7bn budget, saying that costs are not "under control."
Lord Forsyth said: "The costs of HS2 do not appear to be under control. It is surprising therefore that the Government has not carried out a proper assessment of proposals to reduce the cost of HS2—such as lowering the speed of the railway or terminating in west London rather than Euston—which the Committee recommended in 2015. A new appraisal of the project is required.
"If costs overrun on the first phase of the project, there could be insufficient funding for the rest of the new railway. The northern sections of High Speed 2 must not be sacrificed to make up for overspending on the railway’s southern sections."
The report's findings come in the same week that another report, backed by the former Brexit Secretary David Davis, concluded that six other rail projects in Yorkshire and 22 more nationwide could be funded if HS2 were to be scrapped.
They include a supertram”network for Leeds and a new main line between Yorkshire and Carlisle.
John O’Connell, chief executive of the TaxPayers’ Alliance, which published this week’s findings on alternative schemes, called the project a “white elephant”.
He said: “We have long argued that HS2 is a waste of taxpayers’ money, and it’s good to see the House of Lords Economic Affairs Committee make those same arguments in their report.
“Instead of spending £56bn on a vanity project, the Government should heed our report and look at the many excellent alternatives on offer. Taxpayers are demanding more for their money, so it’s now time to scrap this white elephant in favour of some popular and positive alternatives.”