Liberal colleague Russell Broadbent had to show the former health minister to her new seat when Parliament resumed on Tuesday, four weeks after she resigned her position on the frontbench.

She arrived armed with paperwork to keep herself busy without a portfolio to focus on, but, two days later, she was back on her feet making a private members’ statement.

Ms Ley called on the Murray Darling Basin Authority to manage water recovery targets in the southern part of the basin and cut the amount of “environment water” taken to meet targets at the expense of Farrer farmers.

“My communities, large and small, depend on us getting this right,” she said.

“Water is the lifeblood of my electorate and the reason so many of us live, work and raise our families in western NSW along the Murray and Murrumbidgee rivers.”

The MDBA is evaluating social, economic and environmental issues in the basin plan, and visited four drop-in sessions over the past month, but Southern irrigators have called for a full review.

Ms Ley said the basin plan’s “sustainable diversion limit” – the maximum amount of water which can be taken for consumptive, not environmental, use – should be increased by more than 5 per cent.

“I stand ready to advocate for legislative change to either alter this figure, if indeed we can achieve the outcomes with less water being removed, or express the amount as a single new target of, say, 2100 gigalitres,” she said.

“When I meet my farmers, they remind me: what would our regional economy look like if we had not lost so much of this permanent water?”

Meanwhile, Prime Minister Malcolm Turnbull introduced a bill on Thursday to establish a new entitlements watchdog to oversee and report on MPs' expenses, developed in the wake of Ms Ley’s travel scandal.

“This is the first step in the biggest reforms to the management of parliamentary expenses in more than a generation,” he said.