Rival parties moved to amend a newly passed anti-corruption law Wednesday amid mounting questions over its scope and constitutionality.

The move comes just a day after the National Assembly passed the bill despite controversy over its possible violation of individuals' constitutional rights and what critics argued could be excessive legislation.

The bill's hasty passage is widely seen as an attempt by lawmakers to please voters ahead of next year's parliamentary elections as public demand for the legislation has been high in a country where corruption involving public officials causes national outrage.

The so-called Kim Young-ran Law, named after the former Anti-Corruption and Civil Rights Commission chief who proposed the legislation in June 2011, subjects public officials, journalists and private school faculty to a maximum penalty of three years in prison or a fine of five times the amount they accept in money or valuables, if they take money or valuables worth more than 1 million won ($908) from one person in one installment, regardless of whether it is in exchange for favors or related to their work. For gifts that are work-related and worth 1 million won or less, the penalty is a fine of up to five times the gift's value.

The bill was drawn up to tighten loopholes in existing anti-corruption rules under which public officials cannot be punished for accepting expensive gifts and services unless there is evidence of reciprocity.

On Wednesday, both the ruling Saenuri Party and main opposition New Politics Alliance for Democracy acknowledged the need to review the details of the law.

"We will humbly listen to all opinions about loopholes or side effects and in the one and a half years of preparation, if there is a need to supplement the legislation, we will do so," Rep. Yoo Seong-min, the floor leader of the ruling party, said during a party meeting.

The ruling party especially raised concerns about excluding civic groups from those subject to the law and the vagueness of what constitutes an illegal request for a favor.

The main opposition party, meanwhile, expressed concern about the possibility of "targeted investigations" by prosecutors and the police, and excessive legislation.

"There must be parallel efforts to build an institutional guarantee against the prosecution's abuse of authority through prosecution reforms," Rep. Kang Gi-jung, NPAD's chief policymaker, said in a phone interview with Yonhap News Agency.

In a press conference at the main government complex in Seoul, the ACRC's current chief, Lee Sung-bo, vowed to do all he can to ensure the new law takes root at an early date.

"We will work hard to resolve the controversy by supplementing the areas the public is concerned about in the process of drawing up relevant enforcement ordinances and rules," he said. "We will do our best to ensure that this law, which carries the people's desire for integrity, becomes a new milestone that makes our society more transparent and clean."

A survey conducted by polling agency Realmeter showed that 64 percent of those surveyed approved of the bill's passage. The survey was conducted on 500 adults on Tuesday and had a margin of error of plus or minus 4.4 percentage points.

The bill's passage had been delayed amid wrangling over various details, including a clause that requires public officials to report a family member's acceptance of a bribe.

Critics argued that the clause infringes on the constitutionally-guaranteed freedom of conscience and destroys family relationships.

Ahead of the bill's passage, the rival parties agreed to keep that clause but limit the scope of another clause to apply the law only to public officials and their spouses, not their other family members. The official, not the spouse, would be subject to the relevant punishment.

The parties also agreed to allow an 18-month grace period for enforcement of the law from the date of its proclamation.

Last year, South Korea climbed three notches in an international corruption awareness ranking to 43rd out of 175 countries, according to Transparency International, the Berlin-based anti-corruption watchdog.

South Korea scored 55 out of 100 in the 2014 Corruption Perceptions Index, with high scores meaning low corruption. (Yonhap)