Earlier, only prime minister, chief ministers and ministers were now allowed from visiting constituency ahead of the polls.
The ECP amended its code on complaint of candidate Saifullah Khan in connection to NA-108 by-election in Mandi Bahauddin on June 8.
He alleged a female minister of Punjab, Hameeda Wahiduddin, recently announced development package for the constituency, which was an attempt to influence by-polls.
The ECP issued notice to Ms Wahiduddin and sought her reply within a week.
