During the early part of Wenger's spell at the Gunners, Wenger won two League and FA Cup doubles, managed the 'invincibles' to a league title in 2004 and two other FA Cup triumphs between 1998 and 2005. Last season the Frenchman ended a nine year trophy drought by winning the FA Cup, overcoming Hull City 3-2 after extra time at Wembley in May.
In an interview with the Daily Express, Allardyce described the side Wenger had built in his first five years as 'amazing' but then suggested his entire ethos had changed.
The Hammers' boss said: "Arsene Wenger's change of culture at Arsenal was a major success. Getting players like Ian Wright and Tony Adams to change their way of thinking, coupled with his buying policy, was amazing.
"His first five years were amazing. But I don’t know what happened to him after that.
"He seemed to change his whole ethos - I don’t know if it was because he had the new stadium to pay for, you will have to ask him.
"It became all about smaller, pretty footballer than it did about the big hard talented footballers who won the ball and won him the key games.
"Never mind being able to play, they could mix it, too. He was challenging Manchester United on a regular basis and went a whole season without being beaten. They were fantastic.
"Then all of a sudden this change of culture happened where every midfielder seemed to be 5ft 8in and they lost that steel."
Some have questioned Arsenal's ability in recent years to engage in physical battles and almost fight teams on the park. The likes of Patrick Vieira and Martin Keown seemed to relish any needle in a game and would take on a side that challenged them physically.
The style of play undertaken by Wenger still gets applauded for its eye-catching interplay and willingness to keep the ball on the floor but Allardyce has accused them of becoming too one dimensional.
Ever since their last league title success in 2004, whenever Arsenal have looked like challenging for the title, they seem to falter around March or April, but have always managed to do enough to secure Champions League football.
The side is still blessed with some top class footballers but Allardyce isn't the first, and is unlikely to be the last high profile person in the game to question whether Arsenal lack the physicality to take on certain sides.
It would be interesting to hear what Wenger's reaction would be to Allardyce's comments, but Arsenal fans would hope it would spur their manager on to prove any doubters wrong, and that they are a force to be reckoned with.