Newcastle’s Under-21s will take on League One Sunderland’s first team in the tie, which will be played on January 8 (7.45pm kick-off).
The clubs have been drawn against each other in the last 16 of the competition at the Stadium of Light, with United given an initial allocation of 2,800 seats.
As of 6pm on Tuesday evening, there were only 539 tickets left of the original allocation.
As previously reported, Newcastle will ask Sunderland for more tickets if they do indeed sell out their allocation, which now seems a matter of time.
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The 2,800 figure disappointed some Newcastle fans, who were hoping for a larger allocation at the Stadium of Light given the clubs haven’t met at senior level since March 2016.
Competition rules state that away fans should be allocated at least 10% of a stadium’s capacity, which works out at just under 5,000.
However, Sunderland executive director Charlie Methven said last week that felt that that number would be “too high”.
“The rules of the competition are that the away team gets 10% of the stadium capacity,” said Methven.
“In our case, that’s just under 50,000, which would mean more or less getting 5,000 tickets, and Newcastle have asked us for that allocation.
“I think our view, and the view of our internal security team, is that’s maybe a bit high.”
There was trouble at a reserve derby between Newcastle and Sunderland at the Stadium of Light last season.
A number of seats were damaged by visiting supporters during the Premier League International Cup quarter-final, which was won by United after a penalty shootout.
And there were disturbances at Vale Park earlier this month at the Checkatrade Trophy derby between Port Vale at Stoke City, who were backed by a 4,000-strong travelling following.
Tickets for the Wear-Tyne derby, priced £15 for adults and £5 for concessions, are on sale to season-ticket holders with 50 or more away points.
Newcastle beat League Two club Macclesfield Town on penalties in the last round of the competition.
The club also won all three of its group games.