(Adds Social Changes poll)
WARSAW, Aug 23 (Reuters) - Poland's ruling nationalist Law and Justice (PiS) party, hit by two high profile resignations, lost ground in two polls on Friday ahead of October's election.
A poll by Kantar showed PiS losing 5 percentage points, while a Social Changes poll showed a drop of 2 percentage points.
The Kantar survey was the first poll that has shown the gap between PiS and the pro-democratic opposition narrowing significantly in the campaign for the vote in which the deeply divided nation will elect members of the upper and lower houses of parliament.
The figures come after a deputy justice minister resigned this week following a website's report he sought to discredit judges critical of the government's judicial reforms by planting media rumours about their private lives.
His resignation followed that of the PiS parliament speaker for using government aircraft for private trips.
The Kantar poll, conducted on Aug. 22, showed PiS with 39% support, down from 44% on Aug. 13, while its arch-rival the centrist Civic Platform (PO) had 30%, up 3 points since mid-August. The leftist coalition Lewica remained on 11%.
The Social Changes poll conducted from Aug. 16-21 showed PiS on 42.9%, down 2 percentage points, with PO on 30.8%, up almost 4 percentage points. Lewica were down 1.5 points on 13.4%.
According to the opposition the election will decide if the ruling party, which remains at loggerheads with the European Union over issues such as the rule of law, logging forests, CO2 emission targets and refugees, will be able to finish its reforms and install itself in power for decades thanks to planned changes to the constitution.
Polling numbers had held steady, as economic factors such as the ruling party's generous welfare handouts, had prevailed - leading analysts previously to predict the party would weather the storm over the resignations.
But now they are questioning whether that will continue.
"It is all about the commotion over private flights and the deputy justice minister. It may be reflected in the poll and it helps the liberals. Of course one has to wait to see if this is a trend or not," said Rafal Chwedoruk, a political scientist at Warsaw University.
The Kantar poll was conducted for private broadcaster TVN24, while the Social Changes poll was conducted for website wPolityce.pl.
(Reporting by Pawel Florkiewicz, Marcin Goclowski and Alan Charlish; Editing by Alison Williams, William Maclean)