Anglo-Australian mining giant Rio Tinto (ASX: RIO) has pledged another $1 million dollars to the Queensland Premier's Flood Appeal.

This is in addition to $700,000 donated to the fund and $300,000 directly to Emerald charities and organisations in early January.

Rio Tinto Energy chief executive Doug Ritchie said the increased donation followed ongoing flooding across much of Queensland over the past week.

"We have all been shocked by the extraordinary flood events that have impacted much of our state," Mr Ritchie said.

"Queensland is home to many Rio Tinto operations and we have around 7,000 Rio Tinto employees working and living in Queensland, some of whom have been directly impacted by the floods.

"In addition to this donation, Rio Tinto is helping in other ways during this time of need.

"Everyone is keen to do their bit to help their neighbours recover from the damage to their homes, businesses and local communities.

"This is why Rio Tinto has also launched an employee volunteering programme to make it easier for staff to help with the recovery work," Mr Ritchie said.

The programme allows Brisbane-based employees to receive their usual salary and benefits while helping in the clean-up, without having to take annual leave.

Employees are working on recovery projects through the Brisbane City Council's volunteering programme.

"As one of Queensland's largest private employers and a part of this community, Rio Tinto is committed to helping with the ongoing recovery efforts," Mr Ritchie said.