The Free and Fair Election Network (Fafen) has expressed serious concerns over "the ongoing efforts to amend the 1973 Constitution seeking deviation from the basic constitutional framework that requires allocation of seats among all federating units on the basis of population in accordance with the last census," in a press release issued on Tuesday.

"The proposed amendment also seeks a one-off exemption from the requirement of carrying out fresh delimitation of constituencies on the basis of officially published census results," Fafen said about the proposed constitutional amendment which will ensure the 2018 General Elections are held according to provisional results of the 2017 census.

Fafen claims that the proposed amendment, which will change Clause 5 of Article 51, "will change the basic framework of the Constitution if it is passed."

The existing Article 51 (5) requires that the “seats in the National Assembly shall be allocated to each Province, the Federally Administered Tribal Areas and the Federal Capital on the basis of population in accordance with the last preceding census officially published”.

However, Fafen said, "the proposed amendment exempts Fata from the principle of allocating general seats to the provinces in proportion to their populations."

The network said that according to the new formula, Fata's seats will be retained at 12, which is twice as many as it would be allocated according to the proportion of its population. The retention of Fata's seats means a reduction of three general seats in Punjab, two in Sindh and one in Khyber Pukhtunkhwa (KP), the press release noted.

It also demanded Fata and the Capital Territory be allocated reserved seats for women , like all other areas of the country.

"It would be more appropriate to reach a decision on the future of Fata – its merger with KP or status as a separate province – to address the issue of its underdevelopment/under-representation instead of creating deviations from the Constitution to over represent a region in the national legislature," Fafen suggested.

It alternatively suggested specific amendments which would apply to all underdeveloped areas of the country and demanded all territories of Pakistan to be treated equally and proportionally.

The network urged the government to resolve the "highly technical issue" of publication of census results through administrative means.

It said that the Pakistan Bureau of Statistics (PBS) should "officially declare that there will be no significant deviations in the official census results from the provisional data" but demanded all concerns regarding under-enumeration be allayed.

Fafen also demanded that the issue of seats of religious minorities also be deliberated upon before coming to a conclusion on the seat allocation.

The bill had earlier been a cause of controversy as Sindh's largest political parties in the parliament —Muttahida Qaumi Movement (MQM) and PPP — had refused to vote in its favour, citing under-counting in the census.

It was then sent back to the Council of Common Interest (CCI), upon PPP's request, which removed the deadlock on Monday after the Sindh chief minister accepted the formula after a decision to hold an independent audit of a number of blocs was taken.