A visit by a top Chinese official to North Korea this week for a key anniversary of the North's ruling party signaled little evidence of thaw in strained political ties between the two allies, two Chinese experts told a Hong Kong-based media outlet on Monday.

Liu Yunshan, who ranks fifth in China's ruling Communist Party hierarchy, will lead a Chinese delegation that will attend the 70th anniversary of the founding of North Korea's Workers' Party on Saturday.

North Korea's state media reported that Liu will "pay an official goodwill visit," without elaborating further.

This week's visit by Liu to North Korea will be closely watched because of a possibility over whether he could meet with the North's young leader, Kim Jong-un, with China expressing its displeasure over Pyongyang's nuclear and missile programs.

Sung Xingjie, an expert in Korean Peninsula affairs at Jilin University in China, told the South China Morning Post that Liu's visit "just shows that they are maintaining a party-to-party relationship, which is the bottom line for the two sides to maintain communication."

"The visit will not improve the relationship, but they cannot afford to completely ignore each other," Sung was quoted as saying by the newspaper.

Cui Zhiying, a professor of Korean affairs at Tongji University in Shanghai, also told the newspaper that Liu's visit suggested that the relationship between the two allies "is not as bad as people had speculated."

"Other than Pyongyang's nuclear program, the two nations do not have many grudges against each other," Cui said.

Political ties between China and its only treaty ally, North Korea, remain strained, particularly after the North's third nuclear test in February 2013. However, few analysts believe that China will exert enough pressure on the North to give up its nuclear weapons because it could lead to the collapse of the North's regime and hurt China's national interests.

Kim, who took power in 2011 following the death of his father, has yet to visit China. (Yonhap)