Dalbir Kaur said she will try to meet Zardari during his private visit to Ajmer dargah on April 8.
"Mercy petition of my brother is pending with Zardari. I would urge from him to release my brother. Since he will be visiting Ajmer dargah on Sunday, I am also going there with a wish of my brother`s release which is in the hands of Zardari," she told reporters here.
She said the case of his brother was that of a mistaken identity and the Pakistani government should release him as he has already spent 22 years in jail.
Sarabjit has been on death row since he was convicted for alleged involvement in four bomb blasts in 1990 that killed 14 people. His family insists he was wrongly convicted for the bombings. Though Sarabjit was set to be hanged in 2008, Pakistani authorities put off his execution indefinitely after Prime Minister Yousuf Raza Gilani intervened in the matter.