China's ruling Communist Party should cut its more than 80 million members by nearly half to avoid the bloat that felled the Soviet Union, a political scientist has written in a party magazine.

The Communist Party of China is the world's largest political party, having recruited a wide swathe of citizens in recent years in an effort to broaden support as its original ideological underpinning has changed.

More than 90 years after being founded and after 64 years in power, the organisation now has members ranging from business people to students, some of whom join for status or connections and not out of political loyalty.

But Zhang Xien, writing in the People's Tribune -- part of the media grouping that includes the party mouthpiece, the People's Daily newspaper -- said "the rapid expansion of party membership has brought the party huge dangers.

"Creating a mechanism for party members to quit is the top priority for building up the party in the new era," wrote Zhang, a professor at Shandong University.

The Communist Party of the Soviet Union had 240,000 members when it seized power and 19 million when it fell, he said, calling it a "tragic lesson of what happens when a party grows too large with no strong mechanism for members to quit".

He proposed slashing the party to 51 million people by separating out "preparatory" and "honorary" members.

Over the years, loose entrance requirements and poor oversight of those admitted meant that "some members' convictions are shaky, their awareness of the objectives is flimsy", he wrote.

On top of that, the power of the party had attracted "all sorts of people, including various types of speculators trying to use the title of 'ruling party member' to seek personal gain".

Since taking office, China's new Communist chief and state president Xi Jinping has warned that the party could fall apart due to rampant official corruption.

He and the rest of the new leadership have launched a highly publicised campaign to cut public spending and build a closer connection to ordinary people.