The head of the Australian Christian Lobby and former special forces soldier Jim Wallace has "unreservedly" apologised for commenting against gay marriage and Muslims on Anzac Day.

Jim Wallace, the managing director of ACL, wrote on Twitter this morning: "Just hope that as we remember Servicemen and women today we remember the Australia they fought for - wasn't gay marriage and Islamic!"

Tweets ... Jim Wallace. Credit:Andrew Taylor

Mr Wallace was heavily criticised on Twitter for his comments.

"What they fought for was freedom from prejudice and persecution. For all Australians!" one user said in reply, while another wrote: "Perhaps you need to remember that many gay servicemen and women also fought and died for Australia."