The 27-year-old currently plays in his homeland for Velez Sarsfield, but has had spells in Europe with Birmingham City in 2008 and more recently with Italian giants Lazio and Inter Milan.

The signing would mark Sam Allardyce's first foray into the transfer market this summer since it was announced he would be staying at Upton Park after discussions with the board.

Zarate, who is reported to have agreed a three-year-deal with the east London club, would join a front-line including Andy Carroll and Carlton Cole, although Kevin Nolan was the club's top scorer in the Premier League with six goals.

West Ham finished the season 13th and mangager Allardyce has been told he will only continue at the club if he can improve the style of football after receiving criticism from the club's fans.

The Hammers published their list of realsed players this week, signalling the departure of Joe Cole, Jack Collison, Callum Drive, George McCartney and Jordan Spence.