Nazir Hussaid, 35, from the central Punjab province, shot Kosar and Gulzar Bibi, 22 and 28, in the horrific double honour killing, and is now on the run.
The two women were preparing to marry men they had chosen themselves, senior police officer Mehar Riaz said.
Hussaid objected to the love matches and had wanted the women to marry someone within the extended family.
'The brother shot dead both the sisters yesterday and fled the site,' the officer said, that a search was underway.
'It is a simple case of killing for honour,' he said.
Father of the family Atta Mohammad told local reporters that Hussain had 'destroyed everything'. 'He ruined my family, he destroyed us, he destroyed everything' Mohammad said.
The double murder comes days after social media starlet Qandeel Baloch was strangled to death by her brother who said he was 'not embarrassed' to have killed her, reigniting calls for action against the crime.