Below is complete text from SA 610 and corresponding examples in bold & italics
The external auditor shall not use internal auditors to provide direct assistance to
perform procedures that:
(a) Involve making significant judgments in the audit; (Materiality / Audit Strategy / RMM / Use of Test of Controls etc)
(b) Relate to higher assessed risks of material misstatement where the judgment required in performing the relevant audit procedures or evaluating the audit evidence gathered is more than limited; (Eg Inventory Valuation) 

(c) Relate to work with which the internal auditors have been involved and which has already been, or will be, reported to management or those charged with governance by the internal audit function; or (Eg If internal auditor has already worked on salary checking and he has reported to TCWG or Management or Will be reported, then it doesn’t make sense to again appoint him under direct assistance for salary checking)
(d) Relate to decisions the external auditor makes in accordance with this SA regarding the internal audit function and the use of its work or direct assistance. (Eg Whether to use internal auditor for direct assistance / is he reliable  / supervising internal auditor / whether his work is sufficient…. such work cannot be given to internal auditor again)