Pompey have decided to appeal their £15,000 Checkatrade Trophy fine.
The Blues were last night informed by the Football League they had been found guilty of three breaches of selection rules.
This was in respect of breaking competition guidelines with the sides they fielded against Yeovil, Reading under-23s and Bristol Rovers.
A total of 12 clubs have been fined, with Pompey and Luton attracting the maximum figure of £15,000.
Now Pompey have lodged an appeal with the Football League.
A club statement said: ‘From the outset we have made it clear that we are fundamentally opposed to the introduction of so-called ‘B’ teams into any first team league or cup competition.
‘In our opinion, this only serves to undermine the integrity of the competition and Pompey will continue to fight strongly against any proposals.
‘Finally, we would like to thank our fans for their continued support of the club in this important issue.’