A Senate Estimates Committee has shed light on why the use of the word "mate" by security staff at Parliament House was banned.

The staff were ordered not to use the word in August this year.

The Prime Minister John Howard and the Labor leader Kim Beazley objected to the order, saying the expression, "mate", was a part of Australian culture.

The ban was withdrawn within 24 hours.

Hilary Penfold from the Department of Parliamentary Services has told the committee that two families had made complaints that parliamentary security ought to be more polite.

She says she will be more guarded about the briefings staff receive in the future.

"I would certainly hope that what we've done with that particular arrangement for getting information to the PSS officers will improve our chances of not putting out things that make us look a bit silly," she said.

"I suppose I would call it an error of judgment."