Chairman Freddy Shepherd says tickets have been put up for sale on online auction sites at inflated prices.
The match against Celtic on May 11 sold out within a couple of days, with the proceeds going to charities across the North-East.
Shepherd: "We have very strong feelings on this matter. I think it's disgusting that some people would look to make money out of a testimonial, where everyone knows that all the proceeds are going to charity, and try to exploit genuine fans who want to be part of what will be a great occasion.
"If we find out that any of the people who are selling tickets are season ticket holders then we will look at taking action against them."
Dave Pattison (safety officer at St James' Park): "Ticket touting is a criminal offence. The club will take strong action against people who abuse their season ticket facilities and they will be dealt with appropriately."
Let's be honest here, it wouldn't take much to catch these people. Simply offer to buy a ticket, and "Bob's yer uncle". The sooner these people have their season tickets taken off them, the better the place will be. We don't need this type of scum in SJP.