First Interstate Bancorp, which has concentrated on getting its financial house in order by shedding problem loans, is now ready to bolster its lending by taking on more deposits, the company said.

First Interstate was the 11th largest bank holding company in the nation at the end of last year, falling from the No. 9 position in 1989, a sign of its efforts to shore up its financial position.Like others, the bank had been hit by problem real estate loans in the Southwest, meaning a rise in the size of its non-performing loans.

But now the Los Angeles-based bank group says it is ready to obtain some new deposits to use in making new loans.

"We are putting people on notice that we have the capability (to make some acquisitions). Our position is slightly less defensive than before," said First Interstate spokesman Simon Barker-Benfield.

Although he would not say which markets First Interstate was looking at, he said it did have several things in mind that would involve smaller rather than larger acquisitions.

In its latest quarterly filing with the Securities and Exchange Commission on the bank's condition, First Interstate said "Acquisitions of deposits in selected geographic markets may be pursued."

The spokesman said that represented a bit of a turnaround for First Interstate, which since the third quarter of 1989 has been attempting to recover from the massive losses that resulted from problem loans in Texas and Arizona.

Part of the recovery plan involves reducing total assets and that plan continues. Assets at March 31, 1991 had declined to $50.4 billion from $59.1 billion as of Dec. 31, 1989.

In the filing First Interstate continued to be cautious about the outlook for 1991 because of the impact the recession was having on its business.

Chairman Edward Carson has already warned that earnings for 1991 would be well below the $6.79 a share it earned in 1990, before a one-time gain from an accounting change.

First Interstate also warned in the filing that it is still seeing a rise - although a small one - in the size of its problem loan portfolio in Nevada since the end of the first quarter.

"A continuation of these conditions may result in further deterioration in credit quality which in turn may negatively impact . . . results."

First Interstate also said in the filing that operating results could be adversely impacted if a slowdown in the forest products industry continues or deepens.