Speculation last week suggested that the Belgian defender had agreed a £100,000-per-week contract with United and would move to Old Trafford once a fee had been negotiated between the two clubs.
He told Sky Sports News: "I know there has been a lot of talk and a lot of rumours but the only thing I can say is that it's not true.
"Everybody understands my situation at Arsenal and that I have one year left. I understand that people are going to talk but I am here in Brazil and I am enjoying my time and I'm focused on what I am doing.
"We talk a lot when I am at Arsenal but it's not what I am going to discuss here, it is something you are going to have to ask him."
Vermaelen, who is club captain at the Gunners, made only seven Premier League starts last season.