FIFA has listed the kick-off for the June 8 qualifier at 5 p.m. local time (1300 GMT) in Muscat, where day-time temperatures regularly soar above 40 degrees Celsius at that time
"We are working on it and I think it's unacceptable to play that time of the year," German Osieck said in a conference call on Tuesday.
"When some bureaucrats make a decision behind their desk in a climatised room and not considering the actual situation outside, I think that is a very questionable decision."
The country's soccer administration Football Federation Australia had previously expressed their concerns about playing a match in the heat before the time was posted, an official told Reuters, and would write to FIFA again in a bid to have the match moved back into a cooler evening slot.
When asked about the chances of having the match moved back, Osieck struck an ironic tone. "I've been (dealing) with FIFA for quite a while and we know how flexible they are," he said.
The Socceroos' original 9:30 p.m. kick-off time in their last qualifier against Saudi Arabia in Melbourne irked the FFA, who lobbied successfully to have the match played earlier out of deference to broadcasters and fans hoping to attend the midweek match.
Osieck also named a 26-man squad for a friendly against Denmark on June 2 and the World Cup qualifiers against Oman and Japan in Brisbane on June 12, recalling Everton midfielder Tim Cahill and striker Josh Kennedy.
Aston Villa midfielder Chris Herd, named in the squad for the first time, will have his chance to impress selectors at a training camp in Denmark in the lead-up to the friendly.
"I had (Herd) on the list already for the last qualifiers in November but he couldn't make it because of injury," Osieck said of the 23-year-old.
"Hopefully he can do a good job for us as well."
The squad, which also includes stalwart goalkeeper Mark Schwarzer and Harry Kewell, will be cut to 23 in the lead-up to the Oman qualifier.
Squad: Mark Bresciano, Alex Brosque, Tim Cahill, David Carney, Nathan Coe, Adam Federici, Chris Herd, Brett Holman, Mile Jedinak, Josh Kennedy, Harry Kewell, Neil Kilkenny, Robbie Kruse, Matt McKay, Mark Milligan, Lucas Neill, Jade North, Sasa Ognenovski, Nikitia Rukavytsya, Mark Schwarzer, Matthew Spiranovic, Archie Thompson, Carl Valeri, Luke Wilkshire, Rhys Williams, Michael Zullo.