David Higgins, the Australian chief for the massive building project of 2012 London Olympics, is to resign from his post next year before construction is completed, it was announced on Tuesday.

Higgins will leave the job as chief executive of the Olympic Delivery Authority (ODA) in February to run Network Rail, the owner and operator of Britain's railways infrastructure.

The authority's finance director Dennis Hone will replace Higgins.

Higgins was picked up for the ODA job in 2005 after overseeing the construction of some of the venues for the 2000 Sydney Olympics.

He said it had been a "privilege" to lead the authority over the past five years and said he was confident London 2012 would put on "a brilliant show".

Higgins has promised that the transformation of a rundown area of east London into the Olympic Park will not exceed the projected final cost of 7.3 billion pounds (11.5 billion dollars, 8.5 billion euros), well within the overall budget of 8.1 billion pounds.