The comments, directed to opposition spokeswoman for community services Nicole Lawder, came after sometimes tense debate between the two first-term members during consideration of the ACT budget.

The situation appeared to come to a head on Wednesday evening when Ms Lawder suggested Ms Berry might have been "asleep, had selective hearing or didn't have her glasses on" during the sitting.

Ms Berry quickly responded with the insult, drawing laughter from some members.

She withdrew the remark after protests by Opposition Leader Jeremy Hanson and later apologised to Ms Lawder for her use of inappropriate language.

"I apologise to Ms Lawder and to the Assembly," she said during the adjournment debate.

In response, Ms Lawder said that since her election she had listened to Assembly proceedings in silence, without interjecting or interrupting her colleagues. "I had hoped the same courtesy could have applied in return," she said.

"It's one thing to participate in the cut and thrust of the debate, but comments like the one we heard today have no place in our Assembly and contribute to the dim view many in our community have of our proceedings.

"On a more personal level, this type of comment is pretty hurtful for my children and grandchildren to hear on the news, and I find it especially sad that it came from another woman."

Ms Lawder said the Assembly should move on from the comments and thanked Ms Berry for her apology.

Treasurer Andrew Barr earlier denied suggestions from opposition whip Brendan Smyth that he had laughed at the comment and challenged Mr Smyth to repeat the claim outside the Assembly.

A vote to halt the budget debate through a suspension of standing orders was defeated by government members, delaying statements from Ms Berry and Ms Lawder about the incident until the end of the day's business.

Mr Hanson jumped on the cow comment, using Twitter to object to "unacceptable behaviour" by Labor members, including Mr Barr.

The Assembly is expected to pass the 2014-15 ACT budget on Thursday.