The left-arm bowler announced his international retirement at the age of 28 in December 2020, saying he could no longer play under the management and that he was being "tortured mentally".
Amir, who was jailed in 2011 for his part in a spot-fixing scandal, served three months in prison and a five-year ban from all forms of cricket before returning to the Pakistan squad in January 2016.
Part of the team that won the 2009 T20 World Cup and 2017 Champions Trophy, Amir has played in franchise T20 leagues since his retirement.
"I still dream to play for Pakistan!," Amir posted on social media platform X. "Life brings us to the points where, at times, we have to reconsider our decisions.
"There has been few positive discussions between myself and the PCB (Pakistan Cricket Board) where they respectfully made me feel that I was needed and can still play for Pakistan.
"After discussing with family and well wishers, I declare that I am available to be considered for upcoming T20 World Cup, I want do this for my country as it comes before my personal decisions..."
Amir has played 36 tests, 61 One-Day Internationals and 50 T20s for Pakistan since his debut in 2009.
All-rounder Imad Wasim (35) also reversed his retirement decision and made himself available for the T20 World Cup on Saturday.
Pakistan will kick off their T20 World Cup campaign against co-hosts United States on June 6th.
