This may delay the project by six months and will now be completed by September 2009, said developer Emaar Properties.
Originally scheduled for completion at the end of the year, the tower, whose final height is shrouded in secrecy, had its target date earlier put back to next April.
"We are going higher, and this is one of the reasons why the project is delayed," Fred Durie, executive director for Emaar, was quoted as saying in a national daily.
"The luxury finishes that were decided on in 2004, when the tower was initially conceptualised, is now being replaced by upgraded finishes. The design of the apartments has also been enhanced to make them more aesthetically attractive and functionally superior," he said.
Burj Dubai is part of a $20 billion Burj Dubai development, which includes a shopping mall, hotels, and residential buildings.
The company said that world-class designers were brought in from California to re-frame the interior design, and accordingly all apartments are being upgraded following a redesign process that took two to three months.
Durie said that the extra height would pose greater challenges to construction, because of the wind factor created by making a building that tall. In May, 18 days of work was lost due to strong winds.
"The higher you go, the more difficult it becomes to build, as when the wind picks up, work has to stop. Vertical transportation also gets more difficult. This is the problem with going taller," said Durie.
The world's 13 tallest buildings