Mining and construction contractor Macmahon Holdings Ltd (ASX: MAH) says a number of its mining and construction projects in Queensland have been impacted by the ongoing severe weather conditions.

"Our operations in Queensland have been affected by varying degrees over the Christmas and New Year period," Macmahon said in a statement.

"However, the Cameby Downs open cut coal project located near Chinchilla is the only project to be significantly impacted by the current rain and flooding."

"Mining operations at Cameby Downs were shut down on the 10th of January, predominantly due to the difficulty in accessing the site. We expect production to resume as flooding subsides."

Macmahon's Brisbane office, located in South Brisbane has also been closed due to the flood waters impacting the office complex and surrounding areas.

The company said the impact of the floods to its 2011 earnings is yet to be determined.

Chief executive Nick Bowen said the priority for the company was ensuring the safety and well-being of its employees and their families.

"We are working closely with our clients to implement measures necessary to protect the projects and assist our workforce."