Following a dismal 2014-15 season, a strong start to this year saw the Knicks put themselves in playoff contention, but a sudden slump in form has seen them lose 14 of their last 17.
Head coach Derek Fisher was fired and Rambis installed, but the change of management has failed to arrest the decline, with the former Lakers coach now 2-5 in charge.
"We're all frustrated," Rambis told reporters on Monday. "If you're a competitive athlete, I don't know how you can lose games at any point in time and be okay with it.
"So nobody in this organisation is okay with where we're at. And we know we've got to be better. We've got to be a lot better in a lot of areas."
The Knicks next welcome the Portland Trail Blazers (32-28) to Madison Square Garden on Tuesday night.