With controversies and allegations continuing to mar the ongoing presidential race, calls have grown for the ruling and main opposition parties to replace their nominees and install ones with cleaner pasts and clearer views.

Many voters are unfavorable to the two-way race between Lee Jae-myung of the ruling Democratic Party of Korea and Yoon Suk-yeol of the main opposition People Power Party, holding rallies and releasing statements urging the candidates to drop out.

Lee has faced criticism surrounding his family members, and he faces allegations over his involvement in the Daejang-dong land development scandal. Yoon has also been denounced for allegations against his wife, as well as his failure to lead his conflict-ridden election campaign committee.

Some have demanded that former Democratic Party Chairman Lee Nak-yon take the place of Lee Jae-myung for the ruling bloc, and for Rep. Hong Joon-pyo to replace Yoon for the People Power Party. Both alternate picks placed second in their respective party’s primaries.

A survey conducted by Korea Information Research and commissioned by the Cheonji Ilbo with 1,003 voters on Sunday showed that 49.2 percent of respondents wanted a change in the presidential candidate for the Democratic Party. More than 50 percent of respondents favored the candidate for the People Power Party being changed as well.

Yet the reality is that it is almost impossible for candidates to be replaced at this stage, as regulations state that a candidate can only be replaced if he or she voluntarily resigns, dies or is stripped of party membership.

While many favor them as replacements, Lee Nak-yon and Hong are barred from registering as party candidates as they have already lost their primary races. Yet this rule also has an exception of them being allowed if the candidate in place dies, resigns or leaves the party.

Both ruling and main opposition parties have bylaws that nullify the candidacy of their nominees if they are found to have no electoral rights or if they change their party membership.

To be stripped of the right to run for a public official post, the nominees would need to be sentenced to a fine from a court, which is highly improbable considering that the election is only around 60 days away and that no court ruling could realistically be expected to be made before then.

The Democratic Party has a bylaw that allows its nomination to be canceled if the candidate is found to be ineligible to register as a candidate, but Lee Jae-myung is eligible to run for office and the rule does not apply on him.

The People Power Party has no bylaw on this matter, which effectively ensures that Yoon will continue representing the party as its presidential nominee.

Experts have also said the chances of the two main candidates being replaced are small, but a slim chance exists for Yoon to be replaced under some conditions, mainly if the gap in support rating between Lee Jae-myung and Yoon enters the double digits.

"There has to be a public opinion that can lead the discussion into it," said Lee Sang-don, a professor emeritus at Chung-Ang University who served as a politician for the conservative bloc for years, in an interview with KBS on Tuesday.

"The most important things to consider in viewing this public opinion are current lawmakers, senior party officials and conservative media outlets. If they together ask for a candidate replacement, what can candidate Yoon Suk-yeol do about it?"

For more information regarding the survey results, visit the National Election Survey Deliberation Commission homepage.