Blues wing Tom James has played just one season of regional rugby

James, 20, replaces Harlequins back Hal Luscombe, who withdrew from the squad last week for family reasons.

Wales coach Gareth Jenkins has also called up hooking pair Gareth Williams, and Matthew Rees.

That has been forced by injuries to new Leicester recruit Mefin Davies (rib) and Huw Bennett, who aggravated a neck problem in Ospreys' win at Borders.

Wales meet the Wallabies in Sydney on 26 May and again on 2 June in Brisbane.

Cardiff Blues hooker Williams last played for Wales in 2003 but joins Scarlets number two Matthew Rees on the flight down under.

Wales were already weakened in the front row with the withdrawal of Dragons prop Rhys Thomas (ankle), who was replaced last week by 19-year-old regional colleague Jamie Corsi.

James' call-up caps a remarkable first year as a full-time professional, winning a regional contract after bursting onto the scene playing for the Cardiff club side with 11 tries in nine matches.

The Merthyr-born flyer has also represented Wales Under-20s and the Sevens team.

Sonny is a class act and we are lucky to be able to call on someone of his quality Wales coach Gareth Jenkins

"Tom James is a hot prospect, but we wanted to make sure he came through the weekend's action before bringing him in," Jenkins said.

James will bolster Wales' options in the backs along with veteran centre Sonny Parker, who was called up last week after Llanelli Scarlets wing Dafydd James was told he needed knee cartilage surgery.

Uncapped Corsi has made just six starts for the Dragons this season, and his inclusion highlights the lack of tight-head props in the Welsh game.

But Jenkins, who is leaving Chris Horsman behind for a World Cup conditioning program, said: "He has a big future in the game.

"We are both confident and comfortable that he will take the step up and benefit from the opportunity presented to him."

Parker was also originally one of 18 senior players staying at home for the training camp, but could now add to his 21 caps in the two Tests against Australia on 26 May and 2 June.

"Sonny is a class act and we are lucky to be able to call on someone of his quality, experience and undoubted talent to boost the squad," added Jenkins.

"He was overjoyed to take the call and is very much looking forward to touring."

Prop Thomas is expected to be in plaster for three weeks after damaging ankle ligaments and will need another three to five weeks of recovery.

The 24-year-old, capped once, only recently returned from seven months out of the game with a serious chest complaint.

Wales 28-man squad for Test matches against Australia in Sydney on 26 May and Brisbane on 2 June: