'Erratic' Macdonald needs help: Cameron

Labor's Doug Cameron says Liberal senator Ian Macdonald needs some help after he asked him to "speak Australian" during Senate question time.

Labor's Doug Cameron (pic) says Liberal senator Ian Macdonald needs some help. (AAP)

Veteran Liberal senator Ian Macdonald has been told he needs help by the man he scolded for not speaking Australian.

Scottish-born Labor senator Doug Cameron was the target of the insult during question time on Wednesday.

"We should all rally around him," he told reporters of Senator Macdonald's outburst, saying his behaviour was becoming more erratic.