Pompey boss Steve Cotterill handed debuts to recent signings Dave Kitson and Liam Lawrence on Saturday, but the south-coast club failed to secure their first league win of the season.
Pompey have scored just once in their first five Championship games and although they produced an improved performance, it was another frustrating afternoon for Cotterill's side.
David Nugent came closest for Pompey when his shot hit the crossbar, while David Norris struck the woodwork for Ipswich, who remain unbeaten in what has been a promising start to the season.
Pompey made a bright start and Kitson and Lawrence almost combined to put them in front after just four minutes.
Lawrence, who had his loan move to Fratton Park sanctioned on the day of the game, swung over a corner from the left and Kitson rose highest but headed wide of Marton Fulop's goal.
Ipswich responded and midfielder Grant Leadbitter flashed a free-kick over the crossbar two minutes later.
But Pompey were unfortunate not to be in front after 14 minutes when Nugent's strike from the edge of the penalty area rattled the crossbar.
Ipswich were also looking dangerous going forward and just before the half-hour mark Leadbitter's corner was flicked on into the path of Darren O'Dea, but the on-loan Celtic defender volleyed over the crossbar from close range.
Luke Hyam had an opportunity to score his first senior goal for the Tractor Boys but the young midfielder volleyed over the crossbar four minutes before half-time.
Pompey suffered a blow just four minutes into the second half when skipper Aaron Mokoena was carried off with what appeared to be a serious leg injury.
Nugent had another opportunity to break the deadlock after 52 minutes but the former Preston striker dragged his shot wide of the target from just outside the penalty area.
Ipswich were on the back foot and Fulop had to be alert to palm away a venomous strike from substitute Michael Brown.
Pompey continued to knock on the door and Kitson had another chance to mark his debut with a goal but shot wide from 12 yards with 25 minutes remaining.
But Ipswich came close five minutes later when midfielder Norris, already with four goals to his name this season, saw his right-foot drive from 25 yards out strike the post.
Fulop was called into action once again at the other end to tip Nugent's strike around the post and Jamie Ashdown produced a sharp save at the other end to deny Leadbitter to ensure both sides had to settle for a point.