If I'm 100% I have a very good chance of winning the Commonwealths, but unfortunately the injury curse has struck again Tim Benjamin

Benjamin, second at the World Athletics final in Monaco last September, has missed six weeks of training and says he will not be fully fit for the Games.

"The Commonwealths may come a little early for me because of the problems I've had this winter," said Benjamin.

"Something is not right. Whenever I try to run at any kind of speed I get shooting pains."

Benjamin will be the highest ranked 400m runner at the Games in Melbourne.

He slashed almost two-tenths of a second off his previous best in running 44.56 seconds to claim second the season finale in Monaco.

His season had started with another injury set-back when he spent most of March in hospital after a back injection left him with severe headaches and a freak gym accident damaged his knee.

The latest setback is believed to be unrelated to that injury, but the 23-year-old is still unsure of the exact cause of the problem.

He added: "I've missed the best part of six weeks training now and it's so frustrating.