The Election Commission's (EC) May 9 schedule to announce official poll results has been thrown into doubt after the agency on Thursday decided to ask the Constitutional Court to rule on the legality of its method of calculating and allocating party-list seats to clear growing confusion about the issue.

The poll agency had previously said that it would announce the official election results on May 9.

However, the poll agency on Thursday issued a press release stating that the commission has sought the court's ruling on two issues associated with its calculation method.

There are two laws stipulating how the 150 party-list MP seats should be distributed. The laws are Section 91 of the constitution and Section 128 of the organic law governing the elections of MPs.

The decision follows complaints that Section 128 of the organic law may breach Section 91 of the constitution, according to the statement.

Firstly, the EC wants the court to rule whether the EC can calculate in a way that will award party-list seats to political parties that garnered fewer votes than the number required to get a party-list seat under the complicated mixed member apportionment system used in the March 24 election.

Secondly, the EC wants the court to rule if such a calculation method complies with Section 91 of the constitution, according to the poll agency's statement.

Confusion has erupted over the EC's calculation of party-list seats with several small parties that won fewer than 71,000 votes expected to be awarded party-list seats at the expense of larger parties.

Media outlets and academics estimated that the required number of votes for one party-list seat was about 71,000. This was based on unofficial vote tallies released by the EC.

However, a revised EC calculation method would make it possible for small parties which garnered between 30,000-40,000 votes to earn at least one party-list seat, according to the EC.

An EC source said that the agency has decided to seek the court's ruling following complaints that its calculation method based on Section 128 of the organic law on the election of MPs would result in at least 25 parties being eligible for party-list seats according to their share of the vote.

Critics insisted that this calculation method contravenes Section 91(4) of the constitution, which stipulates that any party with fewer votes than is required would not qualify.

The source also said that the EC wanted the court to clear up confusion over the matter before proceeding to calculate and allocate party-list seats and endorse the official poll results.