The 22-year-old is reportedly in negotiations with a switch to the Blues.
Curtis’ agent, Patrick Conliffe, of Full Contact Sports Agency, revealed he was in talks with Kenny Jackett’s side.
However, Shiels believes Conliffe wanted to get the Republic of Ireland under-21 international ‘in the shop window to improve his financial gain.’
And the Candystripes manager insists Curtis won’t be moving to Pompey any time soon.
‘We have to do what’s best for him and that’s not the case here,’ Shiels told the Derry Journal.
‘The agent hasn’t handled it well and he’ll not be going to Portsmouth at this moment in time.
‘I’m not saying he’ll never go to Portsmouth but the speculation came from the agent – totally.
‘He just wanted to get him in the shop window to improve his financial gain and that’s all it was.
‘What Ronan needs is a new agent. None of the other agents would’ve let this happen.’