A military helicopter carrying officials assessing damage from a 7.2 magnitude earthquake has crashed in southern Mexico - everyone onboard the chopper survived but 13 people were killed on the ground with another 15 injured.

Five women, four men and three children were killed at the crash site and another person died later in hospital.

The interior department said those onboard suffered only minor injuries.

Jorge Rosales, a reporter aboard the helicopter when it crashed, described harrowing moments as the pilot lost control and the helicopter attempted to land in a swirl of dust.

"The moment the helicopter touched down it lost control, it slid - like it skidded - and it hit some vehicles that were stationed in the area," he said.