Australia should hold a referendum in 2019 and adopt fixed four-year terms for the federal Parliament, Liberal MP David Coleman says.

In an opinion piece published in Fairfax Media on Thursday, Mr Coleman argues that a longer term with a fixed election date would give government more time to implement complex policy reforms, end the uncertainty around election timing that begins every two-and-a-half years or so and that it would be more transparent.

Under Mr Coleman's proposal, while lower house MPs would be elected for up to four-year terms, senators' terms would be stretched from six to eight years.

This is similar to the situation in the New South Wales Parliament but different to the Victorian Parliament, where all members of the lower and upper house serve four-year terms.