The former QPR sponsors hold a 30-acre plot on the Old Oak site where the west London club hope to build a new 40,000-seater stadium.
Rangers have support from all the major bodies required to build the new ground as soon as 2018, but Cargiant is seeking to scupper their plans.
Cargiant managing director Tony Mendes is a QPR season-ticket holder, but the company has released a statement denying discussing selling the company's land with the club.
"We are very surprised by QPR's PR campaign regarding a proposed new stadium in Old Oak Common and in particular on land owned by Cargiant," the statement read.
"The company are not in negotiations with QPR and will not enter into any future talks with the club.
"The company will announce in due course details of its own scheme for the regeneration of its land holdings that will incorporate the residential units, jobs and community facilities that the GLA detailed in their vision for the regeneration for the area.
"Cargiant's commercial arm of the business views this opportunity as a long-term investment opportunity."
Cargiant bosses rejected the notion of QPR obtaining a Compulsory Purchase Order (CPO), a legal function which allows bodies to claim land without the owner's consent if considered in the public interest.
QPR could seek council backing to obtain such an order against Cargiant, but the company remain unfazed by the prospect.
"In regards to the threat of CPO, there is no legal basis on which to serve a CPO on Cargiant. We are a willing developer," the statement continued.
"This is also not a 'tool' to increase the land value to QPR or anyone else. If the company wanted to pursue this route, it would be talking to other developers, which we are not.
"We are fully committed to regenerate our land. We have the funding and the professionals in place to do it."
Rangers chairman Tony Fernandes released a statement in December detailing the club's new stadium plans.
The New Queens Park project has Greater London Authority, Network Rail and Genesis Housing Group backing.
The club aim to regenerate the area along with their proposed move from Loftus Road, pledging to build 24,000 new homes and create 55,000 jobs.
QPR were unavailable for comment, but the Press Association understands club bosses remain confident they will be able to press ahead with plans.