East China's boomtown Shanghai Municipality's population is expected jump a whopping 17 percent to 22.5 million by 2020, said local authorities Wednesday.

The city will grow from 19.2 million people at the end of 2009 to 21.4 million in 2015 and 22.5 million in 2020, said Shanghai Municipal Population and Family Planning Commission in a statement.

The rapid population growth would add to the city's challenges as it was already struggling with overcrowding and overloaded infrastructure, it said.

The population structure was also cause for concern. For a city striving to be a global financial center, only one percent of Shanghai's population, that is less than 200,000 people, are engaged in the financial sector while in Hong Kong the amount is five percent or 350,000 people, it said.

However, the city was seen to be improving in terms of spatial distribution -- as the population was more evenly spread than in 2006. The downtown population density was down by 16 percent to 30,084 people per square kilometer in 2010, while in the suburbs it was up by 31 percent to 1,868 people per square kilometer compared with 2006, it said.

China's population is expected to reach 1.39 billion by the end of 2015, with the urban population set to exceed the rural population for the first time, said Li Bin, director of the National Population and Family Planning Commission Sunday.