Thomas will also compete at the Commonwealth Games in Delhi
Britain's Mark Cavendish will be supported in his bid to win the World Championships road race by Geraint Thomas and Jeremy Hunt.
David Millar is Britain's entrant for the men's time trial with Bradley Wiggins skipping the event in Melbourne from 29 September until 3 October.
Olympic champion Nicole Cooke and Emma Pooley lead the British women's charge.
Cooke and current British road race champion Pooley have been named in both the road race and time trial line-ups.
The 25-year-old Cavendish, who has won 15 Tour de France stages in three seasons, aims to become only the second British winner of the World Championships road race after Tommy Simpson, who triumphed in 1965.
However, the Manxman will have to overcome a numerical disadvantage - his closest rivals will be members of nine-man teams rather than Britain's three - because of International Cycling Union qualification regulations.
Wiggins's fourth-placed finish in the 2009 Tour, coupled with six stage wins for Cavendish and his victory in the Milan-San Remo Classic, earned Britain the full allocation for the 2009 World Championships road race in Mendrisio, Switzerland.
But this season, Cavendish's five Tour stage wins was the best it got for Britain as Wiggins endured a troubled Tour.
British Cycling performance director Dave Brailsford said: "It's no surprise that we've built the men's road team around Mark this year, and both Mark and the coaching staff believe that, of the pool of talent we had to choose from, Geraint and Jeremy would provide the best support to Mark on this course."
Welshman Thomas, 24, performed exceptionally well in his second Tour, occupying the best young rider's white jersey until the race entered the mountains, while Hunt took part in his first Tour at the age of 36 and in his 14th season as a professional.
Cooke, the 2008 world champion, and Pooley, who has enjoyed a strong season on the road, are joined in the road race team by Lizzie Armitstead, Katie Colclough, Sharon Laws, Lucy Martin and Catherine Williamson, with five riders to take to the start line.
Brailsford added: "The women's team is looking strong this year and there are a few medal contenders in there, which puts us in a good position as we can see nearer the time which rider the team will support."
Cooke and Pooley, who won Beijing Olympic silver in the time trial, are two of four riders nominated for the two places in the women's time trial - Laws and Emma Trott are also in contention.
European under-23 time trial champion Alex Dowsett has been named in both the men's under-23 time trial and road race, where he will be joined by Andy Fenn, Jonny McEvoy and Luke Rowe.
Several of the British team including Thomas and Cooke will also be competing at the Commonwealth Games in Delhi which begins on the same day the World Cycling Championships finish.