Prime Minister Scott Morrison has personally approved 30 pay rises for senior staff.

A total of 36 government and non-government staffers are getting paid above the top range in the Members of Parliament (Staff) Act, adding more than $1 million in extra costs.

The figures were revealed in answers to a Senate estimates committee's questions on notice.

Six of the pay rise approvals came from former prime minister Malcolm Turnbull.

AAP

The total number is a jump of 10 from May after 26 staffers were then getting paid above the maximum range.

Under their workplace agreement, government staffers can be paid a maximum salary of $259,000.

The figures were correct as of October 24.

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Meanwhile, Mr Turnbull's political knifing cost taxpayers more than $4.5 million in severance payouts.

Almost $1.9 million went into the pockets of 35 staff who worked for the former prime minister, while 12 staff who worked for former foreign minister Julie Bishop received a total $562,062.39.