Rival political parties will embark on a four-month-long race to seize top provincial posts this week with preliminary candidate registration for the June 4 local elections starting on Tuesday.

The preregistration of candidates will continue until May 14, according to the election watchdog on Sunday. Those who register during the preregistration period can start campaigning ahead of the main candidate registration scheduled for mid-May.

The local elections are for 17 provincial governor and mayoral seats as well as educational superintendents and local assembly members. Because of their nationwide scale, the elections are regarded as a major test of the Park Geun-hye administration that took office a year ago.

A victory by the ruling Saenuri Party would empower the Park administration as it pushes its policies midway through its five-year term, while a defeat portends heavy wrangling with the opposition bloc.

With the addition of Ahn Chul-soo, the IT mogul-turned-dark horse politician, the June elections have gained uncertainties with a break from the hitherto two-way race.

The ruling Saenuri Party and the main opposition Democratic Party are quickening steps to name candidates for the local elections, with both parties vowing to finalize their nominations by April.

Ahn is planning to soon complete the launch of his new political party, with an aim to field candidates for all 17 major governor and mayoral seats.

Key election points are likely to center on the capital region, coveted by all parties who are expected to engage in fierce competition to land their candidates as Seoul mayor and governors in the most populous areas -- Gyeonggi Province and the city of Incheon.

The election watchdog has already launched a crackdown on election irregularities from early signs of heated election campaign activities.

Previous media polls showed that Park Won-soon, the current Seoul mayor affiliated with the Democratic Party, is leading the race against other possible mayor candidates, including Saenuri Party lawmaker Chung Mong-joon and Kim Hwang-sik, former prime minister also affiliated with the ruling party. (Yonhap News)