Perth Glory ace Thwaite has caught the eye for club and country over the last couple of years and his performances have alerted several sides in England.
The likes of Middlesbrough, Leicester, Blackpool and Premier League new boys Crystal Palace are all thought to be keeping tabs on Thwaite.
The 6ft 3in centre-back has been included in the A-League All Stars team to face Manchester United in July and his suitors are expected to watch him in action in Australia's upcoming games against Japan, Jordan and Iraq next month.
Thwaite has experience of playing in Europe after spells with Wisla Krakow and SK Brann and he is thought to be keen on a switch to England.
The player's agent, Jamie Holsgrove, confirmed a number of clubs in England have expressed an interest in Thwaite, but that the defender was focusing on the upcoming games for Australia.
"Michael produced one of his best seasons for club and country and he now has three crucial games ahead for the Socceroos," Holsgrove told Sky Sports.
"There is firm interest in England but his focus now must be with the national team."