Treasury officials repeatedly expressed doubts about a controversial $4m cash payment to a Saudi businessman.

The Government gave the money to Hamood al Ali al Khalaf who was upset that a 2007 ban on live sheep exports had cost him business.

National have argued the influential farmer was standing in the way of a free trade deal with oil-rich Arab nations. Opposition parties have labelled the pay-out a bribe in Parliament.

Hagen Hopkins/Getty-Images Treasury officials made repeated objections ove the deal to Finance Minister Bill English.

Documents, released on Tuesday, show that from early 2012 Treasury officials were reluctant to give the green light to a proposal of initial funding of $4m towards Al Khalaf's desert farm in Saudi Arabia.

They repeatedly warned about a lack of detail in the deal, presented by Foreign Affairs Minister Murray McCully, and warned it would be controversial.

The papers appear to indicate variations of the deal were put before ministers a number of times before it was finally agreed to in 2013.

The plan first came across Treasury officials' desks in January with an unnamed civil servant noting it was submitted "very late" to the Cabinet Office. It was due to be considered by ministers within days.

Details about how much money was needed were also unclear.

"There is also discussion of possible future funding."

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By February the bureaucrats were firm in their opposition.

A pre-Cabinet briefing to Finance Minister Bill English stated: "Note that it is unclear what the benefits of this proposal are or what the potential costs are (e.g. impact on other trade partners). Treasury does not have sufficient information to assess the value of this new expenditure, and whether it is within appropriation.

"Note the procedural problems with the development of this policy – and though Cabinet is asked to note the proposal only, we believe it requires Cabinet's agreement, as a significant policy matter and/or controversial issue. On this basis we recommend not supporting this proposal – or defer..."

A year later a bigger deal with al-Khalaf was on the table.

As well as the $4m payment, the Government would invest $6m in al-Khalaf's desert farm as a "showcase" for New Zealand agriculture.

A further $1.5m would go towards freighting 900 sheep to Dammam for breeding, taking the total package to $11.5m.

Despite some last minute revisions by McCully, Treasury officials were still unmoved by the merits, just before the deal was due to go to Cabinet.

They wrote in a February 7 memo: "It does not provide a clear public narrative about why the funding proposal is being agreed to. Nor does it provide clear details of who will receive the funding and what they will be contractually obliged to provide."

A few days later a briefing to Finance Minister Bill English recommended he not support the proposal - and said Cabinet should be asked to agree, rather than just note McCully's idea.

Their "greatest concerns" were around the lack of detail on spending - "(who is being paid to deliver what) are still unclear."

Officials added: "Very little information has been seen by the Treasury. This makes it difficult to assess the benefits to NZ firms, whether it is within appropriation, and whether procurement guidelines such as open tendering should apply."

"There are also no alternative options presented for Cabinet's consideration."

A week later, another briefing paper extended the same advice not to support the deal: "It remains unclear what the benefits for NZ firms of the proposal will be."

However, emails from early March 2013 indicate Cabinet had given assent and the Foreign Affairs ministry were asking Treasury for help with their budget.

But the following month, ahead of a meeting between English and McCully, officials were still voicing their concern.

A briefing paper said: "Despite this paper being repeatedly sent to Cabinet, it was not consulted with Treasury. It was not clear from the paper what the $10 million committed is being used to purchase."

Papers were delivered to journalists by McCully's office on Tuesday after requests lodged under the Official Information Act. The Treasury papers were published on their website.