The venue, part of Maidenhead-based Rank Gaming, has applied for planning permission from Blackpool Council to expand by a third.
Bosses want to extend into the first floor of its existing premises within the council-owned Sandcastle Waterworld building on the Promenade.
If the changes go ahead, staff areas and the 60-seat restaurant would transfer from the ground floor to a mezzanine first floor and a new card room and gaming areas would be created in their place.
A spokeswoman for Rank Gaming said the company could not comment on the plans at this stage.
The area which the casino hopes to take over has been empty since Granada closed its World of Coronation Street attraction.
Before that it was home to the Bedlam nightclub and a family showbar.
The Sandcastle’s marketing and commercial manager Michaela Boardman said: „These rooms were left vacant when Granada left, and much as we would have liked to have put a family attraction in there, we couldn’t find anyone to put the money in for it. We also decided that we wanted to invest our money in the existing water park.“
The £3.5m Grosvenor Casino opened in 2001 after moving from nearby Station Road in South Shore – premises which are now home to the Paris Casino.
The existing gaming floor boasts roulette, blackjack, poker, electronic roulette and slot machines.
There are 96 full-time employees, and the new development would create four new jobs.
The application by Grosvenor follows a submission by the Noble Organisation, which owns Coral Island, to convert the former Palace nightclub on the Promenade into a three-storey casino which would also include a restaurant and show bar.
That application has yet to be determined by the council.
Meanwhile, people have until June 19 to put forward their views as part of the council’s consultation process on its draft planning brief for the conference leisure quarter on the Central Station site, which it is hoped will home the UK‘s first regional casino.