The Pike Coal Mining rescue team in New Zealand are preparing to send a robot to assess the situation of the 29 miners trapped underground for the last three days.

The new robot, reprogrammed to avoid any new explosions in the mine, will take pictures and assess the toxic gas levels in the area where miners were still trapped since Friday noon.

The Associated Press reported that police superintendent Gary Knowles, the rescue controller, said the New Zealand defense department had upgraded the robot so it would not create a spark and accidentally ignite a new explosion in the mine, near Atarau on South Island.

However, the unstable gas conditions have still prevented rescuers from approaching the mine area.

An explosion occurred at the Pike River Coal Company on Friday, 4 p.m. local time that cut off the power supply to its ventilation system. There has been no means of communication with the 29 workers comprised of 24 New Zealanders, two Australian, two British and one South African, according to a New Zealand Police statement.

"Gas analysis is absolutely critical to deployment of teams underground," Trevor Watts, general manager of New Zealand Mines Rescue, said today at a news conference in Greymouth on the west coast of the nation's South Island, 50 kilometres (30 miles) from the mine site. "We have got to be certain we are not going to compromise the safety of the miners we are trying to rescue and the teams we deploy."

Watts has 30 rescue workers deployed and ready to enter the shaft as soon as evidence from half-hourly gas tests shows it is safe to operate.