The 29-year old striker has signed a two-year deal with the Lions after departing Middlesbrough and Lomas says he wants to put his best foot forward in order to catch the attention of Socceroos boss Holger Osieck.
"I've watched Scott throughout his career and he has a proven track record, scoring at better than one in three games over a long period," Lomas told Millwall's official website.
"He works hard for the team, links play well and can operate in different formations.
"The great thing from our point of view is that he's hungry to do well. He's got his eye on next summer's World Cup for Australia and knows that to get into the squad he needs to be scoring goals for Millwall."