"(We'll) make efforts to make a productive parliament that cares for people's livelihoods, not parliament mired in partisan wrangling," Hong Young-pyo, the floor leader of the DP, said at a meeting with senior party officials.

"We hope that opposition parties keep their promise to make a parliament that prioritizes the improvement of people's livelihoods," he said.

The parties failed last week to narrow their differences about proposals easing Internet-only banks' ownership cap and other key deregulation measures, and agreed to discuss them at the regular session.

The unicameral parliament opens its regular session every September for 100 days. Plenary sessions to handle the passage of those bills are slated for Sept. 14 and Sept. 21.

The bill aimed at raising nonfinancial firms' ownership limit for web-only banks from the current 4 percent is one of the most contentious issues pending at parliament.

The current bank law prevents family-owned conglomerates from gaining control of lenders on concerns that they could easily get credit for their expansions.

President Moon earlier asked for parties' cooperation in easing the web-only bank regulation as he seeks to promote innovation in the financial sector.

But the DP has failed to clearly set its line as some members still oppose the deregulation on concerns that conglomerates could use a bank as their private vault.

The parties are also expected to clash over their review about the government's budget proposal for next year.

The ruling DP is defending the budget proposal worth a record 470 trillion won ($421 billion), saying that bold fiscal spending will bolster the slowing economy.

But the main opposition Liberty Korea Party denounced the government for being indulged in a "fiscal spending binge."

Opposition parties have denounced President Moon's "income-driven growth" policy that calls for households' increased income and spending.

"Moon said there is nothing wrong with the income-driven growth policy. In this situation, promoting what's called joint governance is not possible," Sohn Hak-kyu, the new chief of the minor opposition Bareunmirae Party, told a radio program.

Whether parliament could ratify the April inter-Korean summit deal also will be the focal point at the regular session.

Parliamentary speaker Moon Hee-sang raised the need to ratify the April agreement in September prior to President Moon's visit to Pyongyang for his third summit with North Korean leader Kim Jong-un.

President Moon hopes to make inter-Korean summit agreements survive across administrations through parliamentary ratification.

The National Assembly failed to ratify landmark inter-Korean summit declarations in 2000 and 2007. The failures led the implementation of such deals to fall through after conservative administrations took office.

"A poll showed that 72 percent of people overwhelmingly supported parliamentary ratification of the April deal. There is no reason for parties to hesitate (to approve it)," the speaker said in a speech to mark the opening of the regular session.

"I hope that the ruling and opposition parties are united in promoting peace on the Korean Peninsula." (Yonhap)