Berlin: Germany begin their pre-World Cup training camp on Wednesday amidst injury concerns to several key players as they kick-off preparations for Brazil 2014.

Head coach Joachim Loew will gather his 27-man squad at a five-star hotel in the idyllic south Tirolean resort of St Leonhard where his stars will train in northern Italy for the next ten days.

They play their opening Group G match against Portugal in Salvador on June 16.

There are concerns for the Bayern Munich trio of Germany captain Philipp Lahm (bruised ankle), vice-captain Bastian Schweinsteiger (inflamed knee ligament) and goalkeeper Manuel Neuer (shoulder) who are all nursing knocks.

Loew will also have to asses the fitness of Real Madrid midfielder Sami Khedira and Lazio striker Miroslav Klose with both short of match fitness after long spells on the sidelines with injury.

"With regard to the World Cup participation of Manuel and Philipp, we are optimistic, but both will be treated intensively," said Loew.

"It is good, and also important, that they will be with us from the start in the Tirol, even if they won't initially be able to train."

The most serious question mark is over Schweinsteiger, who is not expected to train before the end of next week and missed Saturday's German Cup final.

Germany have two final friendly matches when they host Cameroon in Moenchengladbach on June 1, then Armenia in Mainz on June 6, before flying to Brazil the next day.

Regardless of injury concerns, Loew said the siuation can "increase the competition for some positions. I want to see players fighting for their World Cup berths.

"The tournament will certainly challenge all the players physically.

"Those who go with us to Brazil must all have top fitness and in a good playing rhythm, that is what the training camp is all about."

The German Football Association (DFB) will also take the Under-23 squad to south Tirol so that Loew has good quality opposition for training matches when he works on tactics.

Loew must trim four names from his squad before Germany's final 23-man World Cup squad is given to FIFA on June 2.

"There will be some hard choices, but that is part of my job," he said.

Sampdoria's Shkodran Mustafi, Freiburg's Matthias Ginter, Moenchengladbach's Christoph Kramer, Schalke pair Benedikt Hoewedes and Julian Draxler, plus Bayer Leverkusen's Lars Bender and Borussia Dortmund's Kevin Grosskreutz are all scrapping to make the cut.