COALITION is the only way forward for the Nationals but there must be changes, the party's Senate leader, Barnaby Joyce, says.

There should be no merger with the Liberals, and the Nationals must do more to support regional Australia and small business, he said.

Senator Joyce recently sparked Coalition tensions by leading a Nationals revolt in the Senate.

In an interview with The Weekly Times, the maverick Senator said the Liberals and Nationals could be out of office "for decades" if the Coalition was dissolved.

He took a swipe at Liberals who've publicly called for action against the Nationals, including Tony Abbott and former Liberal director Shane Stone.

"It's tactically moronic to start an internecine war between coalition parties," he said.

"Those who take a hairy-chested approach don't have the acumen to ask - if there's no coalition, what comes next?"

Senator Joyce said there must be a better coalition process for making decisions, "one that includes all the leaders, not just those on the front bench".

"We're in coalition but at times we'll have different views, and this must be acknowledged. And people should realise that we vote with the Liberals 99.9 per cent of the time."

Senator Joyce said he'd refused to take a front-bench job because it would limit his ability to take a principled stand on issues affecting the bush.

"Where rural Australia has trusted the Nationals to support an issue like the $2.4 billion rural communications fund, we will not compromise or breach that trust in the Senate.

"The Senate's a house of review and amendment. It's where we must stand up for our regional and small-business constituency. The lower house is the place for front-benchers."

He said he hadn't ruled out moving to the lower house, and possibly a tilt at party leadership.

"But that's in the future, it's not on the table at the moment," he said.

A merger with the Liberals would be less effective electorally than having two conservative parties.

"With one net, you only catch half as many fish. It would open the way for other pro-bush parties to emerge," he explained.

On policy issues, Senator Joyce said food "sovereignty" was a priority: "If we can't feed ourselves, we're all under threat."

He said imports had destroyed local industries and changes were needed, including more "protectionist" quarantine policies, "tit-for-tat' tariffs, and better labelling of home-made produce.

A zone tax system with incentives for regional investment was needed, and second-generation bio-fuels offered a "great chance" for new regional activity.

But tougher competition laws were needed to protect small business.

"We must stand up for small business in regional centres and towns. Most farmers also see themselves as small businesses."