Duo sign until end of the season
Daniel Alfei and Marcos Painter will both remain at Pompey for the rest of the season.
Swansea right-back Alfei, 21, has extended his loan deal from the Premier League club after impressing in his four Blues games to date.
Painter, 27, penned a new one-month contract earlier this month, but his recent good form has seen this lengthened.
The former Birmingham, Swansea and Brighton left-back has made a total of 14 appearances since arriving at Fratton Park in August.
Blues boss Richie Barker said: “They were both keen to stay here for longer and we wanted to keep them, so they were a couple of easy deals for us to complete.”