The endeavor of new political parties to forge an alliance may face challenges in garnering momentum in the run-up to the legislative elections in April, as the former leader of the ruling party Lee Jun-seok declared that the opportune moment for the so-called "big tent" strategy has elapsed.

Lee on Saturday openly distanced himself from the increasing calls for a union, while supporters of an alliance argued that the strategy is the best way to gain ground against the current two-party system.

The "big tent" strategy entails a merger among newly formed and prospective political parties unaffiliated with either of the two major rival factions -- the ruling People Power Party and the main opposition Democratic Party of Korea.

“The ‘golden time’ to (merge the new political parties) has already passed,” Lee said in a keynote speech at the launching ceremony of his new party held at the National Assembly.

Lee was officially elected as the inaugural leader of the new party, called the Reform Party (translated), during the ceremony, where other current and future heads of new parties attended in a show of support.

“I do not support the launch of new parties merely based on the hope that we can achieve something. It is important that actual progress is made and our party will view and consider the issue of mergers in that regard,” he added.

Lee however highlighted that the new parties could pursue other forms of alliances, suggesting that each party could cooperate in choosing which candidates to run in different areas, so they won’t be pitched against each other.

Other politicians at Saturday’s event, however, voiced the need for a solid alliance in their congratulatory speeches.

In his speech, Former Prime Minister and ex-Democratic Party Chairman Lee Nak-yon expressed his hope that the parties “could all cooperate to solve an important task of our times.”

“We know what changes and what kind of politics the current era demands of us. We must cooperate in (taking the necessary steps to meet the demands),” he added.

Kim Chong-in, a seasoned election campaign expert in Korean politics and former interim leader of the People Power Party, pointed to a merger among the new parties as a key solution toward success.

“It will be difficult to achieve success in politics by operating separately,” Kim said in his speech.

“I’m certain that the anticipated goals will be sufficiently met if (all new parties) enter the April election united as one.”

After the event, Kim told reporters that a merged party could ultimately lead to taking up “50 to 60 seats” in the total 300-seat National Assembly.

Kim’s latest remarks show a shift from his skeptical view of a strong partnership between Lee Jun-seok and Lee Nak-yon, another political bigwig who is gearing up to launch a party of his own by the end of February.

Kim had said that “it will be difficult (for the two politicians) to merge their parties as their personal and political interests are different,” in a Jan. 16 radio interview.

Observers have already noticed small tensions within the alliance, including over the name of the possible merged political party.

Hope of Korea Chairman Yang Hyang-ja, who launched her own party last year and who has repeatedly expressed support for her new counterparts, said last week that the merged party should adopt the name of her party if launched, during an interview with a local media outlet.

Skeptics say that the shared goal among the new political parties lacks the impetus to bond politicians of different beliefs.

“In the past, new parties that survived in the elections and kept their flame alive were the ones that merged over shared political views, values and philosophy,” former People Power Party Rep. Kim Sung-tae said in a Jan. 16 radio interview.

“It seems the main goals of the current new parties are just to join forces to either punish the Yoon Suk Yeol administration or Democratic Party Chairman Lee Jae-myung (and that is simply not enough).”

The talks of forming an alliance come as several political heavyweights have announced their departure from either the ruling or the main opposition party to launch their own parties in recent weeks.