Motorists are being diverted away from a small section of the lights
Visitors driving along Blackpool Promenade to see the town's lights will be forced to miss some of the illuminations because of sewer repairs.
A section of sewer collapsed on Monday which resulted in the closure near the Hilton Hotel, between Gynn Square and Pleasant Street.
It is hoped the repairs, which have begun, can be done within two weeks.
However, a spokesperson for Blackpool Council said it could take up to two months if the repairs were problematic.
Balfour Beatty have visited the site and a camera survey has found that there is a total collapse of the sewer adjacent to the Hilton Hotel.
According to the council, foul water is backing up in the sewer and as the pipe remains fully in use, there is a danger of the carriageway caving in more if the repairs are not carried out until the illuminations are switched off at the start of November.
Workers from Balfour Beatty are digging out the sewer and will then carry out repairs.
A Blackpool Council spokesperson said: "Unfortunately these works are essential and need to be carried out immediately.
"We have made the diversion as short as possible so visitors to the illuminations don't miss out on too much of the show.
"Hopefully the work will be complete within two weeks and the Promenade can be reopened.
"We will work with United Utilities to do all that we can to minimise the disruption to visitors and residents."
Motorists travelling northbound along the prom are being diverted along Derby Road, Dickson Road and Gynn Square before heading back onto the prom.
Those driving southbound are being re-routed via Gynn Square, Dickson Road and Pleasant Street.