Imran Khan-led Pakistan Tehreek-i-Insaf (PTI) and the Pakistan Muslim League-Nawaz (PML-N) of jailed former prime minister Nawaz Sharif are running "neck and neck", with the PTI ahead nationally and the PML-N ahead in the crucial province of Punjab, according to a poll of polls computed by Gallup Pakistan on the eve of general elections in Pakistan.

The poll of polls constitutes the average of poll findings by five different polling organisations, Gallup Pakistan said in a report.

The "PTI and PML-N are running neck and neck, with PTI ahead in the national vote bank and PML-N ahead in the crucial province of Punjab," it said.

The poll of polls indicates that the dramatic rise of PTI at both national and provincial level is mostly on account of winning over voters of PML-N as well as other parties, it said.

Thus, while the vote bank of PML-N has declined nationally by, 3-6 per cent, depending on the polls considered, from its vote bank of General Elections in 2013, the PTI vote bank during the same time period has nearly doubled from its score of 17 per cent in 2013.

The rise of PTI is explained both by decline of PML-N as well as decline in votes of other parties (as well as share of Independents in the voting pattern), Gallup said.

In Pakistan's First Past the Post electoral system, the ascent of PTI to catch PML-N could cause a major upset for the parliamentary seat distribution in Punjab, it said.

This will, in turn, create two key competitors for forming the federal government. In 2013, PML-N was marked by a head by nearly 100 seats more than the runner up in the National Assembly, it said.

The national average of expected votes computed by Gallup Pakistan ranges between 30 to 32 per cent for PTI; 27 per cent to 30 per cent for PML-N; and 17 per cent to 20 per cent for Pakistan Peoples Party (PPP) led by Bilawal Zardari Bhutto.

According to poll of polls computed by Gallup Pakistan, there are still nearly 12 per cent undecided voters who to make the forecast for elections murky and unpredictable.

In Gallup's own poll findings, the figure of the undecided voters dropped from 21 per cent two month ago to 13 per cent in the final week. Nearly 6 per cent of them switched to PTI, it said.

"Our analysis suggests that the profile of the undecided voters is close to the profile of PML-N voters. If these undecided PML-N voters decide to join PTI fold or go back to PML-N in large numbers the situation may change drastically. That is why we think that the undecided voters may tilt the balance of the forthcoming election in Punjab and thereby determine the fate of the Federal Government," Gallup Pakistan said.

The five polling organisations/publishers taken for the poll of polls are Gallup Pakistan Survey conducted for Geo/ Jang Group, IPOR Survey, Pulse Consultants Survey conducted for Geo/Jang Group, Roshan Pakistan Survey, SDPI/ Dawn Survey.

On the margin of error, Gallup Pakistan said, every individual poll also comes with a margin of error of its results, ranging from 1.5 to sometimes as high as 3 percentage points if the sample size is small.

The five survey works included in the poll of polls report were conducted between May 1 to July 11, 2018.