The Belgium international has notched 16 goals in 28 appearances since joining from Genk in the summer, including a double in Villa’s 3-3 draw with Everton last time out.
And Allardyce is hoping to frustrate Paul Lambert side’s poor home form even further by containing the talents of Benteke on Saturday.
"He's the biggest threat. He's the man who scores the goals for Aston Villa on a regular basis, he's the focal point for their attacks in that he not only scores goals, but he holds the ball up, he's strong," said Allardyce.
"He's had a fantastic start in what must have been a very disappointing season so far for Aston Villa. It says a lot for what he is as a player when he's producing what he is in a team that's been struggling for results.
"We can ill afford to let Aston Villa get off to the sort of start they did against Everton. We've got to avoid that at all costs and play our way into the game, making sure we don't give them any opportunities to score."
West Ham have recorded six homes wins in the league so far this season, but converting that form into victories on the road has proved far more difficult and Allardyce sees their weekend visit to Villa Park as a chance to turn fortunes around.
He continued: "Everyone knows the responsibility of turning around our away results - they must get better.
"We are Jekyll and Hyde, there's no doubt about it. It does niggle me that we can't quite find the same type of form away from home that we've been producing all season at home.
"We've got a fantastic opportunity to change the results we've had recently away from home on Sunday, given that we had a big boost in confidence with a well-deserved win against Swansea last week."