"These are centuries-old traditions, and I will continue to defend them," Israr Ullah Zehri, who represents Baluchistan province, told The Associated Press Saturday.
"Only those who indulge in immoral acts should be afraid."
The women, three of whom were teenagers, were first shot and then thrown into a ditch.
They were still breathing as mud was shoveled over their bodies, according to media reports, which said their only "crime" was that they wished to marry men of their own choosing.
Zehri told a packed and stunned Parliament on Friday that Baluch tribal traditions helped stop obscenity and then asked fellow lawmakers to stop making such a fuss about it.
Several lawmakers stood up in protest, describing the so-called honor killings as "barbaric."
Human rights groups accused local authorities of trying to hush up the executions, which according to local media reports and activists took place a month ago in Baba Kot, a remote village in Jafferabad district.