Penang Chief Minister Lim Guan Eng will debate with MCA deputy president Wee Ka Siong - if the latter names the state government leader who allegedly received millions of ringgit in the controversial undersea tunnel project.

In a statement, Lim, who is DAP secretary-general, said that despite his earlier insistence of not wanting to entertain "underling" Wee's challenge to debate on the issue, he was now willing to "bend over backwards" to agree for the debate, provided Wee can give the required proof.

"Will Wee show the courage to name the Penang state government leader alleged to have received tens of millions of ringgit? Failure to do so will prove that this is another example of Wee spreading fake news," he said.

Lim had on several occasions refused to engage in a debate with Wee on the tunnel issue, saying he would only agree if the latter contests in the Bagan parliamentary seat against him, or if Wee convinces MCA president Liow Tiong Lai to instead debate with him, as the DAP number one.

Wee's failure to abide by these calls showed his "contempt of political etiquette and democratic decorum", Lim said.

"Such political etiquette and democratic decorum are accepted rules in democracies such as the United States, where the presidential nominees debate with each other and not against the vice-presidential nominees."

By repeating his challenge to debate, Wee was merely highlighting the "shame" of Liow not daring to debate on the issue, the chief minister added.

He went on to dare Wee to name the Penang state government leader who he (Wee) alleged received tens of millions of ringgit in the tunnel project, like how Pakatan Harapan had named Jho Low (Low Taek Jho) and Malaysian Official No 1 (MO1) as having received 1MDB money.

Wee recently said that DAP must be reeling in shame after both the chief minister and his father Lim Kit Siang were absent from the forum on the issue organised by the MCA that was held in Bagan, despite being invited to attend.