Both the Red Devils and the Gunners are believed to be keen to add a physical presence to their attacking options in an attempt to overall Chelsea - who possess colossus Didier Drogba - at the top of the Premier League.
The 23-year-old Brazilian, real name Givanildo Vieira de Souza, has a release cause in his contract allowing him to leave for no less than €100 million.
However, an offer of around €20m is believed to be enough to convince Porto to part ways with their star attraction.
Hulk, named after his likeness to actor Lou Ferrigno who played comic book hero The Incredible Hulk, has netted 10 league goals in 35 league appearances for the Dragons since arriving from Japanese outfit Tokyo Verdy - where he bagged 44 goals in 53 J. League outings.
As a result, Old Trafford supremo Sir Alex Ferguson is thought to be a keen admirer of the front-man, who he believes can help lift the goal-scoring burden seemingly laboured onto Wayne Rooney following the departure of Cristiano Ronaldo to Real Madrid.
While Arsenal chief Arsene Wenger has made no secret of his desire to sign a new forward following the loss of Robin van Persie through injury.
And Hulk's agent, Teodoro Fonseca, has admitted that there is interest in the player from the Premier League.
"The big clubs in England have been in contact," he said in the News of the World.
"They have asked about his contract situation but any decision about his future rests mainly with the directors of Porto. I think we could be discussing a move.
"I am calm about the situation and so is the player because he has an excellent future. I think we could be discussing a move in April or May."
