The Harper government says Conservative MPs and senators will begin voluntarily disclosing more details of their travel and hospitality expenses.

Liberal MPs and senators have already begun publicly posting their expenses and Liberal Leader Justin Trudeau is challenging the Conservatives to do the same.

Government whip John Duncan says the Conservatives will work with opposition parties to develop a system for more transparent and open reporting of expenses.

But in the meantime, he says Conservative parliamentarians "will do it themselves."

The decision comes amid an ever-growing scandal over allegedly fraudulent expense claims filed by three former Conservative senators and one former Liberal senator. The government is taking steps today to suspend Pamela Wallin and Mike Duffy from the Senate, without pay.