Constitutional yes however like all free speech, it is home to limitations as we see in Article 19
19. Freedom of speech, etc.-Every citizen shall have the right to freedom of speech and expression, and there shall be freedom of the press, subject to any reasonable restrictions imposed by law in the interest of the glory of Islam or the integrity, security or defence of Pakistan or any part thereof, friendly relations with foreign States, public order, decency or morality, or in relation to contempt of court,
1[commission of] or incitement to an offence.
And the courts of Pakistan spoke of greater restriction to government officers and this was held in
2004 SCMR 164 where the court held that freedom of expression is an essential part of a democracy and through persual of Article 19, the courts held that despite so such freedom is not absolute and is home to restrictions of reasonable nature and reasonable classification can always be allowed and is permitted in law. The court then held that for government servants, it is even more essential for such restrictions to be placed since if such an absolute right is allotted to them, then they have the power to create anarchy in the society
In
PLD 2002 Sc 514 the court held that freedom of expression in the press is extremely important however highlighted that the press is not empowered to defame a person and is restricted in its publication of defamation. The court compared the two Articles pre and post amendment which i shall reproduce.
Article 19 original
“Every citizen shall have the right to freedom of speech and expression and there shall be freedom of the press, subject to any reasonable restrictions imposed by law in the interest of the glory of Islam or the Integrity, security or defence of Pakistan or any part thereof, friendly relations with foreign States, public order, decency or morality, or in relation to contempt of Court, defamation or incitement to an offence”.
Article 19 amended.
“Every citizen shall have the right to freedom of speech and expression and there shall be freedom of the press, subject to any reasonable restrictions imposed by law n the interest of the glory of Islam or the integrity, security or defence of Pakistan or any part thereof, friendly relations with foreign States, public order, decency or morality, or in relation to contempt of Court, commission of or incitement to an offence.”
Note; This was in 2002 and it was amended again later on which is the definition you see at the start.
The court stated that while defamation has been removed however the article does not licentiate the press to publish such material which may harm or cause damage to the reputation, honor and prestige of a person.
Now moving on, in the article above, it has been proven that Article 19 for parliament is Vast in nature due to constitutional addition of Article 66 which is not available to others. So a parliamentarian in the parliament can say things that a normal person would be restricted in saying, Defamation being a major part of it for example If Ayaz Sadiq was to say that Ali Zafar was a misogynistic pig and is a symbol of sexual exploitation in the film industry then there would be no case however if the same was said by a person or a pamphlet then there would be defamation. You see the difference.
if the parliament was supreme, empowered so to amend and remove constitutions and general say of supremacy then it could be argued that they enjoyed absolute freedom however the parliament is based on trichotomy of power in Pakistan and as such is not just not supreme but is a product of the constitution, holder of power as vicegerent while its true owner is supreme and is in balance with two other institutions. In such a case the parliament cannot go against the very frames of the constitution i.e Islam, Federalism, parliamentary system, Trichotomy of power (The legislative limitations basically). The parliament cannot go against them
I am not at all sure that this holds true for India, and need to read up on it before reacting.
However the parliamentarians are also
home subject to limits and the courts decided that these limits are found in the nature of the constitution. You see if the parliament was supreme, empowered so to amend and remove constitutions and general say of supremacy then it could be argued that they enjoyed absolute freedom however the parliament is based on trichotomy of power in Pakistan and as such is not just not supreme but is a product of the constitution, holder of power as vicegerent while its true owner is supreme and is in balance with two other institutions. In such a case the parliament cannot go against the very frames of the constitution i.e Islam, Federalism, parliamentary system, Trichotomy of power (The legislative limitations basically). The parliament cannot go against them and then this is also held in the parliamentary rules of business where a member is given vast powers of Freedom of Expression but is curtailed through the limits mentioned in section 31 of the National Assembly Rules.