Amber Holt failed in her bid to crack the egg on Mr Morrison, but hit him hard enough to make his head jerk forward.

This was revealed for the first time on Monday afternoon after the now 25-year-old pleaded guilty to common assault. Police said Holt put an egg in her pocket before entering the CWA state conference in Albury that Mr Morrison addressed on May 7 about 11am.

She planned to break the egg on his head "as she does not like him as he was not voted into the position". But the egg fell from her hand to the ground "and the accused has struck the back of the head of the prime minister, jolting his head forward".

Doubt about the degree of seriousness attached to attacking such a senior politician has led to her sentencing being adjourned for two weeks, for the assault and to possessing cannabis for which she previously pleaded guilty.

Magistrate Imad Abdul-Karim drew both the defence and the prosecution's attention to the nature of a common assault in NSW law.

He highlighted how such a charge at the Commonwealth level could incorporate, under the criminal code, attacks on an elected public official.

"The difficulty I'm having trouble handling (is) the gravity of the offending."

Mr Abdul-Karim said there was "no place for violence" in the community, especially during a political campaign where any protests should be peaceful.

Holt planned her offending, he said, from the point when she understood Mr Morrison was going to be in Albury - she heard this on the radio while driving into work in Albury - to buying the eggs from Coles.

Before adjourning sentencing to July 23 he explained the reasons for doing so to Holt, who occasionally sobbed during the hearing. This was in strong contrast to her arrival, having delivered a cheery "good morning" to waiting media.

Prosecutor Sergeant Andrew Coombs told Mr Abdul-Karim that he needed more time to more closely look at the Commonwealth legislation and to consider the "harm" involved.

Earlier:

A woman who "rolled" an egg over the head of Prime Minister Scott Morrison during an election campaign event in Albury has pleaded guilty this afternoon to common assault.

Amber Holt was due to also be sentenced on Monday, but the matter has had to be adjourned for two weeks.

She had previously pleaded guilty to possessing cannabis.

The adjournment is to allow both the prosecution and the defence further time to consider the actual "harm" of the assault.

Magistrate Imad Abdul-Karim had pointed to a similar Commonwealth charge that encompassed an assault on an elected public official.

That, he said, would be appear to be of a far greater seriousness than the meaning of an assault under NSW law.

"The difficulty I'm having trouble handling (is) the gravity of the offending," he said.

IN OTHER NEWS:

Mr Abdul-Karim said there "no place for violence" in the community, but especially during a political campaign.

Holt, he said, had invested a great deal of planning into her offending, from the point when she understood Mr Morrison was going to be in Albury to going to a supermarket to buy eggs specifically to carry out an assault.

Before adjourning sentencing to July 23 he explained the reasons for doing so to Holt, who occasionally sobbed during the hearing.

"I understand your honour, she said, "thank you."

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