NSW Waratahs parted ways with head coach Rob Penney on Sunday after five defeats in five games left the team bottom of the Super Rugby AU standings.

The Waratahs lost 46-14 to the Queensland Reds on Saturday, putting them 22 points adrift of the table-leading Reds.

Injuries and the departure of key players have hampered the Waratahs this year, leaving Penney, who managed Munster from 2012 to 2014, and his coaching staff to rely on an inexperienced squad.

"The decision to part ways with Penney was not taken lightly," NSW Waratahs CEO Paul Doorn said in a statement.

"Being the coach of the NSW Waratahs is one of the most high-profile and high-pressure roles in Australian rugby.

"Rob is extremely professional and has put a great deal of effort into the role. However, the on-field performances this season have not met expectations and we feel that, in the best interests of the Waratahs, now is the time to make a change." 

The Waratahs said assistant coaches Jason Gilmore and Chris Whitaker would take charge of the team for the remainder of the 2021 season.

Penney had said the youthful Waratahs needed to recruit experienced players after the loss to the Reds.

"There's no lack of effort and the boys are working really hard out on the field and no one's rolling over," the New Zealander had said.

"But it's a massive project. We need resources, we need to strategically recruit in a couple of areas so that the organisation can move forward more quickly than just relying on the youthful guys to come through."