Forest's existing plans to increase the ground's capacity from about 30,000 to 42,000 through the rebuilding of the Peter Taylor Stand and extension of the Bridgford Stand look to be just the start of a stadium rebuild under Marinakis.
The Premier League club bought the land after a deal was agreed in July which has secured the Reds' future at their home for 126 years.
The owner spoke on the plans and how a huge waiting list has made him want to build on the already huge stadium.
"What we need to do is have a bigger stadium.
"We have a lot of supporters and a huge waiting list for season tickets and I'm sure a 50,000-seat stadium will be full watching our team and our passion."
"That is where the team belongs and where the tradition is," said the Greek business man.
"It's most important for the town of Nottingham and this is something I want to be able to finalise and for the years to come to have one of the best stadiums in England.
"This is my prime target right now."