The GTMC has urged business travellers who are intending to petition against HS2 to “reconsider”.
It also called for a cross-party consensus on the controversial high-speed rail link.
“For HS2 to truly realise its potential its development needs to be strategic and we believe links to Heathrow and Europe are key in order to allow immediate and direct interchanges for business travellers between modes of transport,” said GTMC chief executive Paul Wait.
“As the voice of the business traveller we would actively encourage those considering to petition against HS2 to reconsider.
“In turn it is the impact on UK plc and future growth of the economy where the benefits of HS2 will be most keenly felt.”
The GTMC has continually backed the HS2 project and been vocal in its support.
The call comes as MPs meet to debate the second reading of the High Speed Rail bill in the House of Commons today. A number of Tory MPs are expected to oppose plans for the £50 billion scheme, although the government should comfortably win the vote.
Construction of the London-West Midland stage could begin around 2017 and be opened by 2026. The second phase to Manchester and Leeds may be completed by 2032.
Research from the GTMC has shown that increased capacity and connectivity between the north and south can offer “clear benefits” for the UK business traveller in terms of cost, connectivity and productivity.
The study showed almost 70 per cent of millennial business travellers (those aged 18-29) support HS2.