Dic: on someone's part, on the part of someone

• There is no need for any further instructions on my part.
• This insurance plan involves a bigger investment on the part of employers than most of them may be willing to make.
• It was a mistake on my part and I apologized for it.

1. PHRASE : PHR with cl/group | If you talk about a feeling or action on someone's part, you are referring to something that they feel or do.

2. coming from someone.

... Cobuild, http://idioms.thefreedictionary.com/on+the+part+of