The government of Punjab government beefed up security for 45-year-old Asia Bibi in Sheikhupura jail, where she is currently on death row, officials said.
The step was taken after authorities were alerted that a cleric had announced a bounty of Rs 30 million for any person who killed the woman.
Asia Bibi is also facing the threat of a suicide attack by the "Moaviya group", a militant organisation, The Express Tribune newspaper quoted its sources as saying.
An intelligence report issued last week alerted authorities about this threat.
Aslam Pervaiz Sahotra, senior vice president of the Pakistan Christian Democratic Alliance, told PTI that a cleric named Maulana Muhammad Yousuf had announced the reward for anyone who killed Asia Bibi shortly after Governor Taseer met her in prison last year.
"Following this, the government directed the Jail Superintendent to ensure the safety of Asia Bibi by all means," Sahotra said.
The Christian community feared Asia Bibi might be killed in prison like Robert Fonish, another person accused of blasphemy who was murdered in Sialkot two years ago, Sahotra said.
Asia Bibi was sentenced to death last year after being convicted under the blasphemy law for insulting Prophet Mohammed.
She denied the charge and said she was framed by a group of Muslim women with whom she had a row.
Taseer, who backed a call for Asia Bibi to be pardoned, was gunned down in Islamabad on Tuesday by a police guard who said he was angered by the Governor's criticism of the blasphemy law.
According to official figures, 131 people are being held in jails across Punjab on blasphemy charges.
Eleven of them have been sentenced to death, including Asia Bibi, who was the first woman to be given the penalty.
Though no one has been executed after being convicted under the controversial law, 35 people, including Taseer, who were accused of committing blasphemy or defending those charged with blasphemy have been killed between 1990 and 2011.
They were either victims of extra-judicial killings or found dead in prison in suspicious circumstances.