According to dalek website: Dalek Links, and Daily Star the daleks are to big for him! Here's the article......
According to the Daily Star, the height of the Daleks has been adjusted to accommodate Matt Smith being shorter than his predecessors.
At 5ft 10in, Matt Smith is apparently three inches shorter than David Tennant – so a new set of Daleks has been made so that they can see eye-to-eye, rather than have Matt look up to them.
This seems all a bit odd to us – we don’t recall the Daleks being redesigned for some of the more – ahem – diminutive Doctors of years gone by. (Sylvester McCoy being just 5ft 6in according to his agency, the same height as Patrick Troughton.)
And what about them being adjusted the other way – after all, Colin Baker was a big chap, at 5ft 9in or thereabouts.
From the trailers so far, it’s pretty hard to say if the story is true.
(Source: Dalek Links)