The astronauts taking part in the Shenzhou XIV and Shenzhou XV missions this year will carry out more complicated tasks as China's space station Tiangong has entered the construction phase, a chief designer said on April 17.

A total of six astronauts will stay inside the station upon Tiangong's completion around the end of this year before the Shenzhou XIV crew returns to Earth, according to the China Manned Space Program.

The three crew members of the Shenzhou XIV mission are expected to enter the two space labs - Wentian and Mengtian - for the first time after they dock with the Tianhe core module and complete the space station later this year, said Huang Weifen, chief designer of the astronaut system of the China Manned Space Program and a researcher at the China Astronaut Research and Training Center.

"They will run tests on the labs to make sure they can be put to use and install equipment inside them. Later, the three Shenzhou XV astronauts will launch several space walks and install equipment both inside and outside the station," Huang said at a news conference held by the State Council Information Office on the afternoon of April 17.

Astronauts of both missions will also carry out science experiments and public outreach activities. To prepare the astronauts for more challenging tasks, training in 200 sectors under eight categories has been conducted, she added.

"The training will ensure the astronauts have the knowledge and skills to complete different tasks. Furthermore, we need to ensure they are physically and mentally capable to complete the missions," Huang said.