Visitors will have to wait until early next year for the opening of the world's tallest building in Dubai.

The media office of the city-state's ruler said Wednesday the hulking Burj Dubai will now debut on January 4, a month later than expected.

The new opening date is timed to coincide with the fourth anniversary of Sheik Mohammed bin Rashid Al Maktoum's appointment as ruler of Dubai.

Excavation work on the silvery Burj Dubai, Arabic for "Dubai Tower," began more than five years ago. It has continued rapidly since.

By January 2007, some 3000 laborers — mostly imported from India — had completed 100 stories on the building, at times adding a new floor almost every three days.

The tower is the centerpiece of a 500-acre residential and commercial development in central Dubai.

It is flanked by dozens of smaller brand-new skyscrapers and the Middle East's largest shopping mall.

The tower reached 512m in the summer of 2007, surpassing Taiwan's Taipei 101, previously the world's tallest.

The official opening date has become a moving target, however, as state-backed developer Emaar Properties races to put the finishing touches on its most ambitious project.

Installation of the aluminum and glass panels that cover the colossal tower's outside was completed only last month.

The builder says the more than 92,903sqm of glass panels used on the building's facade could cover 14 soccer fields.

Emaar has repeatedly said it planned to open the building this year.

Less than a month ago, Chairman Mohamed Alabbar told CNN he hoped to have the Burj Dubai ready to open by the Emirates national day on December 2.

The skyscraper stands more than 800m tall. Emaar has yet to confirm is final height.

Emporis, a German company that tracks international building projects, lists the building's height as 818m.