BNZ economist Doug Steel said the amount of credit extended to the agriculture sector continued to grow in the last year or so, but at a slower rate than previously.
In the year to the end of February, rural credit grew 7% or $3.1 billion compared with a year earlier, although Mr Steel said that could be in the form of overdrafts, rather than for capital expenditure or expansion.
Banks say they have not changed lending policies, but concede they are following those policies more closely, which meant access to funds was tighter or more expensive for some borrowers.
The BNZ's head of agribusiness, Tony Arthur, said this also reflected the higher cost of lending on international credit markets and tighter credit rules being imposed by the Reserve Bank.
He said the farming sector had correctly returned to fundamental lending policies after a period when people chased capital gain over cashflow, which had put some farmers under pressure as land prices fell.
Mr Arthur said tight credit in the next year would prevent a return to a flood in the number of farms converting to dairying.
"I am aware of a number of conversions in Canterbury that are close to pushing the start button, but I don't think we will see the numbers we have seen. But I do expect that as the market consolidates, people's confidence will grow in the industry."
Mr Arthur rejected claims banks were charging a liquidity crisis margin on loans, saying the higher rates reflected the international cost of credit.
The National Bank's managing director of rural banking, Charlie Graham, said his bank had not changed its lending policy, but staff did not have the same degree of discretion as previously.
Mr Graham said banks were also requiring more information and more accurate and tighter budgets.
Forecast product prices were still a key input in assessing loans, but he made no excuses for requiring more robust budgets and forecasts.
"We want to make sure there is a buffer in the budgets in terms of cash surpluses, budgets for plant replacement and cash drawings."
Gone were the days when farmers could expect banks to bail them out of a poorly forecast cost overrun or because their business had outgrown their systems and reporting structures.
"It is not something the farming sector has alone. We are seeing it across all business."
Many farmers were still preparing accounts for taxation purposes rather than monitoring their financial performance, but farm businesses were getting larger and more complex and commensurate reporting was needed.
"Some people may find it uncomfortable that here we are pushing them for more detail, but we are under greater scrutiny from regulators and auditors."
New Reserve Bank regulations require banks to increase the amount of capital they retain against borrowing which Mr Graham said would be reflected in higher cost of credit.
"The whole credit environment has changed."
Banks were also looking more closely at their clients, and those perceived as having a greater credit risk would have that risk reflected in their lending conditions and costs.
Rabobank's regional Southern South Island manager Jeffrey Morrison said the bank had grown its lending book faster than its market share, and was still lending money for what he called "good, quality business."
Lending criteria had not changed, but he said some banks lent outside that criteria.
"We have probably seen some lending outside the standards, for example equity ratios in different situations mitigated in other areas."
The criteria priority for lending remained cashflow, personal factors and security values.
Mr Morrison said when considering a loan, his bank would also look at how the acquisition or development fitted in a long-term business plan or family succession.
"They really need to think about the future and what the acquisition or development means to their business."
Money would continue to be available for borrowing provided applications stacked up.
Westpac New Zealand's manager of business banking Ian Blair, said Reserve Bank figures showed Westpac had provided $78 million of the $128 million loaned to the farming sector in the last six months, and it had done so without changing its lending criteria.
The bank had given more decision-making power to its regional managers and he dismissed claims lending decisions were increasingly being made offshore.
Mr Blair said his bank saw a positive future for New Zealand agriculture.
If banks chose to invest in Asia, Mr Blair said that could squeeze the amount of capital available for agriculture.