OTTAWA - Sen. Mike Duffy is going to find his Senate paycheque will soon be a little lighter.

The Senate is going to start clawing back Duffy's salary after the Prince Edward Island senator refused to repay almost $17,000 in disputed expense claims before Saturday's deadline.

Duffy also opted against having an outside arbitrator hear arguments in the case.

A spokeswoman for Sen. Leo Housakos, chairman of the upper chamber's internal economy committee, says the Senate must now garnishee Duffy's salary under the dispute resolution policy set up in response to the auditor general's audit.

Jacqui Delaney says the details of how much will be clawed back, and for how long, are still being worked out.

The Senate previously withheld a percentage of Sen. Patrick Brazeau's salary until the upper chamber recouped about $49,000 in disputed housing expenses.