Cavani is expected to join Ole Gunnar Solskjaer’s side on a free transfer before the transfer window shuts on October 5.
The 33-year-old left Paris Saint Germain in the summer after seven season in the French capital, scoring a club record 200 goals and winning six Ligue 1 titles.
The Uruguayan stalwart, who boasts 50 international goals in 116 caps, will bring a lot of experience to the United attack if the deal goes through.
But a number of South American superstars have flattered to deceive after completing big money moves to the red half of Manchester in recent years.
The likes of Juan Sebastian Veron, Diego Forlan, Radamel Falcao, Angel Di Maria and Alexis Sanchez did not make the grade before moving on to pastures new.
Giggs is however adamant Cavani will prove to be a big hit should he move to Manchester United.
“It goes without saying he's a world star,” Wales manager Giggs said at a press conference.
“My second game (as Wales manager) was against Uruguay and Cavani scored and I was really impressed with his work rate and quality.
“It's about how quickly he beds in. We have seen South Americans who haven't really come and done it like Falcao, [Angel] Di Maria and Sanchez, but Cavani, with his work rate, you expect him to make it.”
“I think Cavani will have no problem with the size of the club. He's got the experience to handle that.
“But eyes will be on him straight away and if he does come, he'll have to hit the ground running because the pressure will be on.”
