The Gunners - who beat QPR 2-1 at the Emirates Stadium on Boxing Day, where striker Olivier Giroud was sent off for a headbutt on Nedum Onuoha - make the short trip across east London to Upton Park looking to maintain their push towards the Barclays Premier League's top four.
West Ham may have lost at Chelsea on Friday's lunchtime kick-off, but remain confident following a superb opening half of the campaign, which has seen both Liverpool and Manchester City beaten at the Boleyn Ground.
Irons' boss Sam Allardyce is in no doubt of the contribution made by Song, the loan signing from Barcelona offering a formidable defensive shield for the likes of Cheikhou Kouyate, Stewart Downing, Enner Valencia and Diafra Sakho to stretch the opposition.
Having helped mould Song from the raw talent playing in French Ligue 1 at Bastia, Wenger is not surprised to see the 27-year-old, who left Arsenal in 2012, producing solid displays in the Premier League once again.
"I brought him here at the age of 17 and kept him despite all the opinions against him. He developed into a very good player, so you don't need to convince me he is a good player," said Wenger of Song, who started on the bench at Chelsea.
"I think he was a very good player when he was here and he didn't play a lot when he was in Spain - you see players like Santi Cazorla who always looks stronger (when they play regularly)."
Arsenal can leapfrog West Ham with victory on Sunday, and are just two points behind fourth-placed Southampton, but ahead of Tottenham only on goal difference.
With so little between the sides around the Champions League places, Wenger just wants his players to concentrate on continuing their recent positive form, which has seen just one defeat from eight in all competitions.
"I don't give importance to the table at the moment," he said.
"There are 20 games to go. It is very tight and it is down to consistency now.
"We know every game now is down to consistency and reproducing the performances.
"We need to prepare quickly, focus quickly and that is an ability we want to show at West Ham."
Wenger is now well versed the in the traditional English hectic Christmas schedule.
"We want to stay in the game, to sleep well and then (go) again," he said.
"It is very quick and interesting as well."
Defender Laurent Koscielny (calf) could be available, while midfielder Alex Oxlade-Chamberlain (groin) also faces a fitness test.
With Giroud now suspended for three matches, Theo Walcott is expected to return to the attack, having been on the bench against QPR.
Goalkeeper Wojciech Szczesny knows Arsenal cannot afford to turn in a below-par display against the Hammers.
He said on Arsenal Player: "We have to be at our best again because West Ham have been brilliant recently.
"It is going to be a difficult game, but I am hoping for three points."
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