The accusation was made by New Zealand First MP and Minister for Children Tracey Martin during a fiery debate on a member's Bill brought by the National MP which allows some foster parents or guardians to open KiwiSaver accounts for their wards.
The two clashed last time the Bill was before the House over claims by Mr Walker that New Zealand First was going to support an expansion of the number of children covered by the proposed law change - it did not do so.
That ill-will continued yesterday, Ms Martin saying she could not follow the usual formalities of congratulating an MP for getting a member's Bill passed.
''We will work with officials now to try and do better,'' Ms Martin said.
''We will work constructively and collegially without abusing people and shouting at people and belittling them when they have no power to respond to him [Mr Walker].''
Ms Martin said she had never seen behaviour like Mr Walker's in her nine years in the House, and he had behaved that way ''not only at every reading since the first reading but also, disgustingly, at the committee of the whole House''.
''Officials cannot do anything else but sit, at the whim of the member whose Bill it is, behind him during a committee stage and be there at his beck and call should he need their help.
''Yet those officials, in this instance, had to sit there as they were accused of being power-grabbing, heartless - didn't care about children.
''That's an unfortunate adjunct to a Bill that should have been able to be celebrated as it went through the House.''
Mr Walker said he had ''absolutely not'' yelled at or abused officials, and video footage of the committee stage showed no-one was behind him.
Mr Walker's KiwiSaver (Oranga Tamariki Guardians) Amendment Bill eventually passed its third reading and will now become law.
Mr Walker said the law change meant meant many children would not be unfairly disadvantaged when planning for their futures.
''The Bill will now only apply to foster children under the care of a legal guardian, which only accounts for about 10%. However, it is a step in the right direction for these children.''
