Mobile phone companies Telenor Pakistan and Ufone confirmed to the BBC that the PTA has sent them a "dictionary" of banned words and expressions.
The PTA has reportedly ordered operators to begin screening text messages by November 21.
"Ufone say they are now working on how to block the offending words," said a BBC story. "A letter dated November 14, apparently written by Muhammad Talib Doger, an official at the PTA, has been leaked to Pakistani media.
"It states that mobile phone operators should begin screening the words, provided on a list attached to the letter, within seven days."
The BBC went on to quote Anjum Nida Rahman, corporate communications director for Telenor Pakistan, as saying, "We have received both the dictionary and the memo and we're discussing a way forward."
Wilson Chowdhry, Chairman, British Pakistani Christian Association, has told the ASSIST News Service that one of those "offending" words is "Jesus Christ."
In a message sent to ANS, he said that among the words and expressions that have to be blocked are Jesus Christ, 'bewaquf' (meaning 'foolish'), and bakwaas (meaning 'nonsense').
"The inclusion of the name of Jesus Christ within this list of offensive words is another example of the intense hatred that resonates within Pakistan towards Christians," stated Chowdhry.
"Such censorship would be received with great animosity in the democratic countries of the West. Moreover such intervention flies in the face of the freedoms of expression that Pakistan's Government has committed the nation too.
"It beggars belief that Jesus Christ could be considered a word offensive to Muslim's as he is written about as a great prophet in the Quran. It would seem that Pakistani Muslim majority hatred for Christians exceeds the love for one of their own prophets.
"The selection of other words raises further questions. I am baffled at terms such as 'Athletes foot' and 'flatulence' receiving a ban when they are commonly used medical terms."
Pakistan has seen a big increase in mobile phone use in recent years with 100m Pakistanis are now estimated to be mobile phone users.
It is unclear what penalty users will face if they text the word 'Jesus Christ'.