After the cabinet approved a third runway to be built at Heathrow and the National Policy Statement on Airports was published on June 5, a vote of MPs must be held within 21 days.
The MPs have the final say on whether a new runway is built or not.
The Labour party had set out four tests on which it would judge its support for a third runway at the airport, and has now admitted that the current expansion plan does not pass these tests.
Criteria included increased capacity being delivered, CO2 emissions reducing, minimal noise and local environment impact and the benefits of expansions being felt across the UK and not just London or the South East.
The party's Shadow Transport Secretary Andy McDonald said that the current expansion plan failed their first three tests and the final test was not yet met.
He also said that while 15% of the new routes are promised to be reserved for domestic travel, that in practice this would in fact be as little as 1%.
Mr McDonald said: "Labour has always argued that airport expansion must meet our four tests. After careful and rigorous consideration, we are clear that they have not been met.
"Heathrow expansion is incompatible with our environmental and climate change obligations and cannot be achieved without unacceptable impacts on local residents.
"The improved connectivity to the regions of the UK cannot be guaranteed and there are unanswered questions on the costs to the public purse and the deliverability of the project.
"We support vital investment in our country's transport infrastructure, but every investment must be tested on whether it provides real value for money and sustainability.
"A third runway at Heathrow fails this test."
Latest indications suggest MPs will be asked to cast the final vote on Heathrow expansion in the House of Commons on Monday (June 25) or Tuesday (June 26).
A Heathrow spokesman said: "We are disappointed that Labour have disregarded much of the evidence on how their four tests will be met by Heathrow expansion.
"The independent Airports Commission - after its 2.5 year, £20 million study - found Heathrow's plans for a north-west runway deliver on all fronts including carbon, noise, air quality and nationwide benefits.
"Despite the decision, we retain the support of trade unions and many backbench Labour MPs and will continue to engage constructively with the Labour Transport Team as we deliver a lasting legacy for future generations, fulfilling our commitments to the economy and the environment."
While Labour will not enforce a whip on its MPs, forcing them to vote a certain way, it is not yet clear whether the Tory government will enforce a whip to make sure its expansion plans are voted through.
If the government imposes a three-line whip, it would create an awkward situation for Boris Johnson . The Uxbridge and South Ruislip MP famously promised to "lie down...in front of those bulldozers and stop the building, stop the construction of that third runway", speaking to protesters.
As a vocal opponent of the third runway, the Foreign Secretary could face having to resign his senior cabinet post over the issue, as convention dictates any cabinet minister must resign before voting against the government on a three-line whip.
Paul McGuinness, Chair of the No 3rd Runway Coalition, said: “We welcome the Labour party’s announcement that they'll be urging parliament to reject the Government's Heathrow policy.
"By rejecting this proposal, Labour will demonstrate the importance of environmental conscience and commitment to ensuring that investment in infrastructure projects is properly scrutinised. It is now up to SNP and Conservative MPs to realise the deep and serious flaws with this proposal.
“This is now an issue of environmental conscience for MPs. Voting for the Government’s Heathrow policy would make a mockery of any MPs’ commitment to our environment.
“This announcement by Labour affirms that the Government and Heathrow have failed to provide the robust details on a range of economic, environmental and financial issues for their expansion plans. The promises made to local communities, business and the regions of the UK on environmental mitigation, jobs, connectivity and economic growth can simply not be delivered.
“We urge MPs of all parties to vote against the Airports NPS when it comes before Parliament next week.”