Sky Sports sources understand that Chris Wilder and Richie Barker are the front-runners for the Portsmouth job.
Oxford United have already confirmed they had given permission for Wilder to talk with Portsmouth, whilst Barker has been free to talk following his exit from Crawley Town late last month.
A host of names are known to be in the frame, but at the moment it is Wilder and Barker who are seemingly top of Pompey chairman Iain McInnes' short-list.
Local reports claim former players Steve Claridge, David James and Hermann Hreidarsson have also spoken with the club, who are still interviewing candidates for the role vacated by Guy Whittingham.
"We have done our homework, we really have," said McInnes.
"And we have taken some excellent advice from some very impressive people along the way.
"Obviously, we are aware this is an extremely important appointment for the football club - and have treated it as such."
Current caretaker Andy Awford is also believed to have been considered for the role.