Cliff Harrison, project director for Bovis, whose previous experience includes the massive Bluewater shopping centre in Kent, said the firm would spend this year working on the power station itself.
This will include bolstering the four chimneys, which have suffered from corrosion, and the construction of two towers in the centre of the power station to hold up a new roof.
Harrison said: "This work will mitigate as much risk as we can on this kind of build. We do not want to find a surprise when we go into construction."
Bovis is expecting that the job will convert from construction management to a fixed-price deal once the major risk factors in the power station have been dealt with.
Harrison said the £600m value was just a rough estimate for the final cost of the scheme. He said: "We want a target price position by the middle of this year and firm that up by 2005."
Harrison said the firm was planning to complete the shell-and-core of the scheme in mid-2008.
When finished, the new structure will include two five-star, 1000-room hotels as well as conference and banqueting facilities able to accommodate up to 3000 people.
Client for the scheme is Hong Kong developer Parkview International.