The statement by Charles Sturt University's political science professor Dominic O'Sullivan comes after last week's ballot draw for the May 18 election.

The last time there were only four candidates was during the 2004 election when the Nationals' Kay Hull was elected.

In 2016, there were six candidates while 2013 had 10.

Professor O'Sullivan said that while the reduction from six to four was not significant, it does perhaps suggest that independents and minor parties do not believe they have strong chances.

"The Riverina is a very safe seat for the Nationals, so other than the other major parties, nobody else has a realistic expectation of winning," he said.

"You're going to get minor candidates standing to make a distinctive point or perhaps even just for fun."

However, he said the fewer candidates "should not be read into too much".

"If there had been a drop of 20 to four, maybe we'd start looking for explanations," he said.

Mr McCormack reminded constituents about his work in improving infrastructure, health and economies across the electorate.

"I've been delivering for the Riverina since I was elected in 2010," he said.

"You only have to look at the record amount of funding that we've invested in hospitals, in schools.

"[There is a] 25 per cent increase in the Roads to Recovery funding for each of the 12 local government areas that I represent."

UAP candidate Richard Foley said the party has "policies I believe are going to fundamentally transform this country".

"This country is in peril and it needs a total change of direction and neither of the major parties are going to give us that," Mr Foley said.

"Our intent is to be holding the balance of power at the next government.

"We've got empty dams; rivers drying up; and, scandals left, right and centre."

ALP candidate Mark Jeffreson said it is only the incumbent Riverina MP who thinks the Nationals are safe in the electorate.

"We don't think his seat's safe, we think that regional Australia has been let down by the Nationals," Mr Jeffreson said.

"He has nothing to say about climate change except we should all pray for rain - that's not a solution to it.

"We're the only ones taking reasonable and proper actions on mitigating climate change."

Similarly, Greens' candidate Michael Bayles said this election will be fought on the major issue of climate change.

"We've got a plan to tackle all that with our climate change policy - to transfer over to renewables by 2030," Mr Bayles said.

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