Pompey have revealed that ‘effectively’ season tickets are no longer able to be sold.
The Blues have this week smashed through the 14,500 barrier as fans continue to snap up their seats.
However, Fratton Park’s 18,931 capacity is now under pressure to accommodate demand for match-day purchases.
In addition, an initial 2,300 seats must be allocated to away supporters.
Tickets are now on sale for home matches against Rochdale (August 5), Walsall (August 19), Rotherham (September 3) and Fleetwood (September 16).
And with empty seats in the process of being snapped up, it restricts the ability to sell season tickets.
Pompey’s chief executive, Mark Catlin, said: ‘In extreme circumstances – and under a specific set of circumstances – if someone wanted a season ticket, as always we would do what we can to assist.
‘However, effectively season tickets are now no longer relevant because the first four home games have gone on sale and seats in the home ends have already been purchased throughout the stadium on a game-by-game basis.
‘Historically, once the early bird closes, you only tend to sell, give or take a few hundred extra.
‘But this year it has been slightly higher due to the demand for tickets generally and supporters concerned about match-day access choosing to purchase season tickets to guarantee it.
‘The increase in season-ticket sales has led to a self-fulfilling prophecy of an ever-growing demand for the tickets that are actually left for sale.
‘Our problem has been compounded by not being able to sell season tickets in the Milton end because of the obligation to give the away club a minimum of 10 per cent of available capacity,
‘We can only open up for sale when the away team sells fewer than 1,300.’
Regardless of such problems, this summer’s season-ticket tally represents an outstanding return.
It is indicative of the continued support demonstrated by the Fratton faithful towards a club on its way back up.
And Catlin is delighted with the fan response.
He added: ‘We should not be discussing this as any sort of negative, it’s a massive positive and a problem most other clubs would love to have to deal with.
‘It shows what I have always known – this is a huge club and moving forward there are no limits to just how big we can become.’