A bitter battle between National Party politicians and staff is undermining the authority and threatening the leadership of Australia's Deputy Prime Minister.

Key points: Pacific nations backlash forces Government backdown on a special agricultural visa

Pacific nations backlash forces Government backdown on a special agricultural visa Stalled visa plans reveal a bitter battle within the federal National Party

Stalled visa plans reveal a bitter battle within the federal National Party Efforts underway to undermine the authority and leadership of Michael McCormack

The tension has reached the point where senior figures in the party are openly calling on Michael McCormack to "muscle up" amid frustrations he has been unable to deliver policies his colleagues want the government to adopt.

The latest flare-up surrounds calls for a special agricultural visa for farm workers, which the government was expected to unveil this week but has since shelved.

The proposed visa would allow for foreign workers to come to Australia to overcome farm labour shortages.

Supporters of Mr McCormack have slammed those within their ranks who they allege have led an effort to undermine his authority ever since he unexpectedly became leader.

The internal dispute over the agricultural visa goes to the heart of the problems engulfing the party.

Party room demands action on farm worker visa

During the week of the Liberal leadership saga, National Party MPs and senators met on numerous occasions.

Multiple sources have confirmed the party room pressured Mr McCormack to make an agricultural visa a top priority in his discussions with whoever was to lead the Liberal Party.

Mr McCormack has repeatedly refused to say what was in the Coalition agreement he struck with Mr Morrison.

In an interview recorded just days after the Liberal leadership change, Mr McCormack was asked if "an ag-specific work visa was part of the Coalition agreement" he struck with Mr Morrison.

"I would like to see an agricultural visa sorted within weeks, not months but weeks. It needs to be, it has to be," he responded.

Less than a week later, Agriculture Minister David Littleproud told a rural press function in Brisbane that an agricultural visa would be announced soon.

The expectations grew further following a report on RN Breakfast that forecasted the possibility of an announcement this week.

Those expectations hit fever pitch late last week when reporters were told an announcement would happen on Tuesday.

Federal Government plans to unveil a new agricultural worker visa have been stalled following concerns from Pacific nations. ( Supplied: Growcom )

Pacific backlash prompts policy backdown

The prospect of an imminent announcement of an agricultural visa sent ripples of alarm through the Pacific.

At the moment, thousands of workers from Pacific Island countries come to Australia every year under the Seasonal Worker Program and the Pacific Labour Scheme.

The programs draw mixed reviews from growers — some heap praise on them, while others complain they are too rigid and haven't delivered enough workers for the industry.

Loading

But they remain hugely popular in Pacific nations, partly because they offer workers there an invaluable source of income.

Experts have estimated that the Seasonal Workers Program has injected almost $150 million into the pockets of pickers from across the region.

So it's not surprising that Pacific Island officials and leaders were aghast at the prospect of a new agriculture visa.

They feared that both programs would be sidelined — and ultimately destroyed — if Australia liberalised its visa regime and welcomed thousands more workers from far more populous nations.

Worse than that, they were angry that the Australian Government was apparently on the brink of making an announcement on a new visa without bothering to consult them.

One labour official in a Pacific Island country — who didn't want to be identified — didn't mince his words.

"I cannot believe [Australia] is thinking about [doing] this," they said.

"Yes, this is a big deal for us, of course it is. It's been a big success and [my country] wants to see more people going to Australia, not less. This could be very bad."

Economists who have championed the Seasonal Workers Programs warned that Australia would also face serious strategic consequences if it pressed ahead with the visa.

"The one thing we can offer Pacific nations that China can't is labour mobility," wrote Stephen Howes from the Development Policy Centre.

"If they were partly or largely replaced by workers from countries such as Indonesia and Vietnam, it would greatly antagonise our Pacific Island neighbours, shred our credibility in the Pacific, and it would drive Pacific countries towards China."

Sources the ABC have spoken with deny there was any intervention by the Prime Minister or Foreign Affairs Minister Marise Payne to prevent the planned visa announcement from proceeding.

However, that message — and the angry response from Pacific Island nations — got through to the Morrison Government.

Agriculture Minister David Littleproud, left, and Deputy Prime Minister Michael McCormack have been at odds on agricultural policies in recent weeks. ( ABC News: Nicholas Haggarty )

Nats leadership in limbo

The National Farmers Federation has long talked about the need for an agricultural visa.

Mr Littleproud has repeatedly spoken of his support for the visa and said he hoped it would be implemented before the end of this year.

The 2018-19 budget released in May included $4.7 million for the next four years "to improve the collection and analysis of agricultural labour force data to better inform and target policy responses".

But late last week the government appeared unwilling to wait for those results and insisted a visa would be unveiled this week.

Recriminations for a lack of announcement this week were swift, with blame immediately levelled at Mr McCormack.

But multiple sources the ABC spoke with insisted policy development for the visa rested with the Agriculture Minister and the Liberal-held Immigration and Employment portfolios.

Almost all the politicians the ABC has spoken with about the planned visa announcement said they were shocked at reports it was set to be unveiled.

They said the visa, in its current state, lacked details including the duration of the visa, how it would interact with other visas, and the types of work that could be carried out on it.

Discussions on those details are ongoing within the Government, with few now willing to predict a special agricultural visa will be adopted.

Mr Littleproud this morning told RN Breakfast he "didn't give a rat's" what policy was implemented, as long as farmers could attract extra workers.

"We will get to a point where we will meet the demands of farmers, who I have heard screaming out for more unskilled labour to get their fruit off their trees," he said.

"The reality is we will be able to do that in making sure that we continue to enrich things like the Seasonal Worker Program that gives priority to those Pacific Island nations that are serving our country so well."

Deputy Prime Minister Michael McCormack, left, speaks with his predecessor Barnaby Joyce and National MP David Gillespie, right. ( ABC News: Matt Roberts )

Mr McCormack and Mr Littleproud have been at odds on a number of policies in recent weeks, particularly Mr Littleproud's refusal to endorse giving environmental water to farmers in drought.

Those against Mr McCormack say he lacks cut-through in the media and has been unable to stand up to senior Liberals.

Mr Littleproud's opponents within the party criticise the first-term MP as being inexperienced, ambitious and having been delivered a ministry on a silver platter.

There is no suggestion Mr Littleproud is actively seeking to undermine Mr McCormack.

He has advocated his support for Mr McCormack and the need for stable leadership within the party.

"Michael is not under threat and I support Michael 110 per cent," Mr Littleproud told ABC Radio Melbourne this morning.

"He has done an amazing job since becoming our leader. He's a different style to Barnaby [Joyce]. No one is going to be like Barnaby."

But there are supporters of Mr Littleproud who are actively seeking him to become the leader.

"Michael needs to muscle-up," one National told the ABC.

The person wants stronger, decisive leadership that brings with it results the party room wants and gives the National Party a clear distinction from its Coalition partner.

When asked if the person thought it would happen, they responded, "we'll see".