Formula 1 analyst Eddie Jordan earlier claimed that the Briton was poised to join Mercedes when his McLaren contract expires at the end of the season.
Hamilton has voiced his concerns over his McLaren car on several occasions this year but a statement has rubbished Jordan's remarks, revealing that he is still in talks with the British team over a new deal.
A McLaren spokesman said: "We have been told by Lewis Hamilton's management team that the story is untrue.
"As mentioned in the past by all parties, we are in advanced discussions with McLaren about a new deal.
"More importantly, at the moment, Lewis is focused on Monza and competing strongly for the championship."
Hamilton currently sits fifth in the drivers' standings with 117 points, 47 adrift of championship leader Fernando Alonso ahead of this weekend's Italian Grand Prix.