Meanwhile, the English Football League have confirmed that the finals over the Bank Holiday weekend at the end of May will also be attended by fans.
England will move to Step 3 on its COVID-19 roadmap from May 17, allowing clubs to welcome back some supporters.
That date sees Barnsley welcome Swansea in their first leg at Oakwell, with the return taking place in Wales five days later on Saturday, May 22 (5.30pm).
EFL clubs will now determine with the relevant local safety advisory groups the exact number of supporters that will be able to attend each fixture in line with national guidelines.
Announcements on ticketing will be made by individual clubs in due course.
Barnsley have confirmed that they anticipate a maximum of 4,500 home fans being allowed to the first leg. No away supporters will be allowed to attend any fixtures in the play-offs.
An EFL statement read: "Given the operational challenges clubs would face hosting both home and away supporters, it has been agreed that there will be no away fans in attendance during the Sky Bet EFL Play-Off Semi-Finals.
"Fans of eventual Play-Off finalists will be permitted to attend the EFL’s showpiece finals scheduled to kick off at the end of the month."
Chief Executive Trevor Birch said: “We are delighted to welcome back fans for the Sky Bet Play-Offs which will be fantastic for our competition and another significant step towards the EFL’s aspiration of having full stadia at the start of next season.
“Over the course of the past 12 months, our clubs have implemented stringent protocols and have worked tirelessly to overcome unprecedented challenges this campaign. Fans’ return at this climax of the season is just reward for semi-finalist clubs who will now use their significant expertise in crowd management to ensure supporters can enjoy a safe and enjoyable return to their much-loved home grounds.
“We are thankful to all those who have helped ensure fans will be able to support their clubs in important fixtures through the semi-finals and we look forward to welcoming fans in yet greater numbers at the play-off finals.”