Oscar Valdes, cabinet chief to Peru's President Ollanta Humala, told reporters that getting to the miners' location could take two or three days longer than anticipated because of new roof collapses inside the Cabeza de Negro mine, about 325km south of Lima.

The miners have been trapped 250m underground in a horizontal tunnel since Thursday when a shaft collapsed.

The nine, aged 22 to 59 and including a father and son, were not injured and remain together. They were being supplied with oxygen, water and soup through a metal tube that they also use to communicate with rescue workers.

Some were able to speak with relatives who are staying near the mine at an improvised camp of about 80 people that also includes police, firefighters and other miners.

While their health was generally sound, some of the miners were suffering from anxiety, not unusual for the emergency situation and its risks.