"We don't have enough time to communicate with voters. In this election, we have no choice but to join forces with others, whether it be a coalition government or an electoral alliance," Hong said.

"Otherwise, we will have to hand the government to the leftist."

His proposal comes as the former ruling party is struggling to survive in the wake of a corruption scandal that led to the ouster of Park Geun-hye as president.

But his remark invited crossfire from three other contenders as it would mean allying with the liberal People's Party and the right-of-center Bareun Party, which was created in January by defectors from the Saenuri Party, the predecessor of the Liberty Korea Party, after a bitter factional feud.

"Gov. Hong's proposal would mean, If things go wrong, the Liberty Korea Party fails to field its own candidate and stands behind Ahn Cheol-soo of the People's Party or Yoo Seong-min of the Bareun Party," Rep. Kim Jin-tae, a staunch loyalist to Park, said.

Former six-term lawmaker Rhee In-je accused Hong of breaching the principle of politics.

"Gov. Hong is too hasty. We can fight in this election only if we manage to keep to our principles faithfully and rally conservative and rightist voters again around us," Rhee said.

North Gyeongsang Province Gov. Kim Kwan-yong has been positive toward a possible alliance but also criticized Hong for going too far and risking backlash from the party's traditional supporters.

The party plans to pick its presidential nominee Friday through delegate polls held on Sunday and public opinion surveys scheduled for Wednesday and Thursday.

Hong maintains a comfortable lead over his rivals in recent opinion polls.

In the latest poll conducted last week by Realmeter, Hong took fifth place following liberal contenders with 8.6 percent. He posted the highest rating among conservative candidates. Kim ranked sixth at 3.8 percent. (Yonhap)