Italy's Gazzetta dello Sport newspaper reported that Pure - the company set up by Jacques Villeneuve's former manager and BAR team boss Craig Pollock in anticipation of new rules in 2014 that demand 1.6-litre turbo engines - had been sounded out as possible replacements for Mercedes.
However, a team spokesman told Reuters: "McLaren has had absolutely no contact with Pure for many months.
"Moreover, the contact we did have with Pure, many months ago, was of an entirely informal nature, and was merely a courtesy gesture."
McLaren have used Mercedes engines since 1996. After winning world titles with Mika Hakkinen in 1998 and 1999, the partnership was strengthened the following year when parent company Daimler bought a 40 per cent stake in the McLaren Group.
But with McLaren branching out and launching their own road car operation, Mercedes instead bought the Brawn GP team after the latter's title success in 2009 and rebranded them in their own name.
McLaren then announced that they would buy back Daimler's stake, a process which was completed at the end of last year.
Their current deal with Mercedes allows for free engines until the end of 2012 but they must then pay the going rate of around €8million a year until at least 2015.
McLaren have also been linked with a return to Honda, who powered them to titles with Ayrton Senna and Alain Prost between 1988 and 1992, but the team said in November that those reports were wide of the mark.
McLaren managing director Jonathan Neale said at the time that they were entirely focused on the relationship with Mercedes.