Designed by HGP Architects, the £35 million scheme was originally due to complete in early 2000 but was beset by problems from the start.
After the consortium charged with delivering the 170m-tall observation tower collapsed, the controversial Millennium project continued to stutter and miss deadline after deadline.
Only last month, difficulties with the 'glass panoramic lift' caused the opening to be postponed.
However, operator Heritage is confident that the tower - which boasts Europe's largest glass floor - will be opened without any further hiccups.
A spokesman said: 'It is a remarkable feat of engineering, a sculptural white icon for the South of England and a new world-class visitor experience.
'The Spinnaker Tower will offer visitors spectacular views over the Solent and out towards the Isle of Wight, across a distance of at least 23 miles.'
It is expected that more than 450,000 people will visit the attraction over the next year.