But the two sides baulked at how to interpret an aggregate of opinion polls they previously agreed to use to decide who would top the ticket.

“I merely promised to yield when the margin of error in the polls falls within 3 per cent, but now the KMT asks to calculate both the 3 per cent up and down, meaning altogether 6 per cent,” said Ko Wen-je, the TPP’s chairman and presidential candidate.

“This is coercion,” Ko said, saying he could not agree to use the method to decide between him and his would-be partner on the ticket, the KMT’s Hou Yu-ih.

03:06

Foxconn founder Terry Guo picks Netflix actress Tammy Lai as running mate in Taiwan presidential bid

Foxconn founder Terry Guo picks Netflix actress Tammy Lai as running mate in Taiwan presidential bid

The two parties signed an agreement on Wednesday to use public opinion surveys conducted between November 7 and November 17 to determine who would top the ticket and announce the result on Saturday.

One of the terms in the agreement was that Ko would yield when there was a 3-per cent margin of error in the polls at the 95 per cent confidence level.

In a meeting that went from late Friday to past midnight, the KMT insisted that Hou was largely ahead of Ko, based on the polls. But the TPP argued that the KMT’s calculation was wrong and that it should be a tie instead.

“[The KMT] calculation is 6 per cent rather than 3 per cent. Do you think it is acceptable? Is it fair?” Ko said, adding he doubted that a joint Hou-led ticket would be able to challenge the DPP.

Ko said he agreed to forge an electoral pact with the KMT because more than 60 per cent of the voters in Taiwan hoped the DPP would be removed from office next year.

03:04

On US stopover, Taiwanese Vice-President William Lai vows to lead Taiwan with peace

On US stopover, Taiwanese Vice-President William Lai vows to lead Taiwan with peace

But KMT chairman Eric Chu Li-luan said he never asked Ko to yield in the event of a 6 per cent margin of error in the polls.

“I specifically told [Ko] in [Wednesday’s] meeting about the margin of error in the opinion polls … and he agreed to concede when there was a 3-per cent margin of error,” Chu said.

But the margins of error in a poll of 1,086 respondents stood at 3 per cent up and down, Chu said.

“This is how it is calculated … But it appears Chairman Ko wanted it at 1.5 per cent up and down instead of the 3 per cent he previously agreed,” Chu said, adding the 1.5 per cent margin of error was for the calculation in a bigger poll of about 4,250 respondents.

Most opinion polls in Taiwan use the 1,086-respondent base for calculation.

But Chu stressed the joint-ticket talks were not yet dead.

“The two sides should quickly sit down to try to resolve this ‘small difference’ in order to team up and work hard to fight for a victory in the election,” he said.

Ko also said he agreed to continue to talk, but in team discussions rather than one-on-one as he did on Wednesday.

Asked if the two sides would be able to meet Friday’s deadline, Ko said: “The election this time is full of surprises, and anything could happen before the 5pm deadline on November 24.”

Taiwan’s KMT, TPP team up for legislative elections to beat ruling DPP

Most opinion polls indicate that a joint ticket headed by either Hou or Ko would fare well against Vice-President William Lai Ching-te, the DPP’s candidate, and Hsiao Bi-khim, who is seen as his favoured running mate. Hsiao is Taipei’s de facto ambassador to the United States.

On Saturday, Lai’s campaign office said the failure of the KMT and the TPP to agree on a joint ticket was expected as the two sides did not have any “common ground” on many issues, and worse still, they each had their “own interests and calculations”.

His office said that without a decision, Lai would be left as the sure candidate in the race.

Lai has been the front runner since he was nominated to run in April, and is expected to announce Hsiao as his running mate on Monday.