'There's plenty of support for Tana'
Umaga's team are again rooted to the bottom of the New Zealand Super Rugby conference after losing six of their eight matches this season.
The most recent defeat was a 16-34 mauling from the Highlanders on Friday, taking their winless streak against New Zealand opposition to 15.
The optimism surrounding Umaga's appointment in June 2015, when he talked of a return to the glory days that brought the Blues three titles, has dissipated as the losses mount.
Redman said he retained faith in Umaga, who is in the final year of his contract.
"There's plenty of support for Tana within New Zealand rugby and the Blues," he told reporters.
"We think he has a great rugby brain, he has the respect of the players, he has my support and the support of the board."
Redman acknowledged fans' disappointment but said dropping Umaga and his assistants was not necessarily the answer, although he said no new contracts had been signed.
"In the end, we haven't been able to deliver and changing coaches every cycle hasn't worked for the Blues previously," he said.
"I think our preferred option would be to try to work with the group we have."
Wellington-born Umaga played 74 Tests, including 21 as captain, leading the All Blacks in 2005 to a Grand Slam victory and a clean sweep of the British and Irish Lions.
After his international retirement in 2005, Umaga joined French club Toulon, where he earned his management stripes as a player-coach.
He returned to New Zealand in 2010, joining the Counties Manukau Steelers, a team he coached to their first Ranfurly Shield success in 2013.
He took over the Blues after John Kirwan and Pat Lam had both failed to turn around the team's fortunes.
The Blues last won the Super Rugby title in 2003 and they have only made the play-offs twice since, most recently in 2011.
Agence France-Presse
