Budget director Bert Lance yesterday defended his past financial transactions, including a $2.6 million personal loan he got from Manufacturers Hanover Trust Co. the same month his Georgia bank established a quarter-million-dollar interest-free account at the New York bank.

Lance said the loan was not related to the account, known as a correspondent relationships, and that the comptroller of the currency was satisfied that the terms of the loan were comparable to other such transactions.

But at his hastily called press conference, Lance also said that he has been told that investigators had discovered an internal memo f rom the New York bank that appeared to link the interest-free account to his personal loan.

The comptroller's office last night refused to release the memo. But a spokesman for the comptroller said that Lance had been "ill-advices" to hold the press conference.

In addition, The Washington Post has learned that the investigation of Lance's financial affairs has broadened.

Comptroller John G. Heimann, shortly after taking office last month, called in the intelligence unit of the Internal Revenue Service to determine whether any information about Lance's bank operations had been suppressed.

Specifically, the investigation it to determine whether the FBI agents doing a security check of Lance before he became director of the Office of Management and Budget were told about information that the comptroller's office had.

In addition to that investigation, the comptroller's office is pursuing an inquiry into Lance's banking relationships, both while he headed Calhoun First National Bank and later, when he became president of National Bank of Georgia.

In his press conference yesterday, Lance noted that, when he went to National Bank of Georgia two yers ago, the bank already had a correspondent account with Citibank of New York, the second-largest bank in the United States.

A correspondent banking account is normally opened by one bank with another in order to expand the range of services available in other cities to the first bank's customers.

He switched to Manufacturers because, he said, he had dealt with that bank for 20 years.

But a source familiar with the Citibank-Lance negotiations claims that Lance's application for a personal loan was turned down by Citibank.

Lance claimed there are no strings to the Manufacturer's loan. The loan, which was to buy a 21 per cent interest in NBG, was collateralized by the stock purchased plus life insurance.

Lance was questioned sharply yesterday about the Manufacturers inner-office memo, which he claimed he knew nothing about until it was shown to him yesterday by the comptroller.

The memo, he said, was dated April 24, 1975, the day Manufacturers granted his loan request. It described how NBG would be expected to maintain a non-interest account of 20 per cent of the "facility," Lance said.

He said he did not know what the word "facility," referred to.

Lance admitted that from the time he got his personal loan, NBG funds were deposited in Manufacturers.

He said the initial deposit was $250,000, but the balance grew to $1.5 million. Lance added that "the account was a very active one because we did a great deal of business with Manufacturers Hanover during that period."

At question is whether NBG's non-interest-earning deposit was maintained at Manufacturers as a compensating balance for Lance's loan.

Lance said that the terms of his loan were an interest rate of 1/2 per cent over the prime rate (the rate a bank charges its best and biggest corporate clients) for the first two years, and 1 per cent over the prime rate for th third year.

Another term of the laon was that Lance would remain president of NBG.

In January, after Lance decided to join the Carter administration, he moved the loan to First National Bank of Chicago, increasing the size to $3.4 million.

The interest rate he paid there was about 3/4 per cent over prime.

With the additional money Lance bought more NBG stock, ending up with 200,000 shares. Lance reportedly paid an average of about $17 a shar for the stock, whose value at one point dropped to half that amount because the bank was forced to write off certain real estate investments.

Because of the drop, President Carter intervened on Lance's behalf, asking the Senate Governmental Affairs Committee to extend a Dec. 31 deadline, suggested by Lance, for selling the stock.

At a hearing July 22, the Senators agreed to the extension, while committee Chairman Abraham A. Ribicoff (D-Conn.) criticized the press for "smearing" Lance.

The main legal question raised by Lance's highly leveraged finances - in January he had debts of $5.3 million - is whether the deposit by NBG with Manufacturers could be constructed as a compensating balance.

Recently, the Justice Department has brought suit, alleging that maintenance of compensating balances were, in reality, misapplication of bank funds - using the bank's funds for personal gain.

An attorney for the comptroller has described five tests used to whether compensating-balance case should be referred to the Justice Department for prosecution. The five tests all of which must be met are:

The borrowing bank officer gets an advantage over other borrowers - normally a lower interest rate.

The correspondent account opened in the lending bank remains dormant, showing no reduction in the balance.

The correspondent account does not receive interest.

The correspondent bank is performing no service, or insignificant service, for the depositing bank.

The size of the correspondent account is sufficient to offset the advantage, such as a low interest rate, enjoyed by the borrowing officer.