WASHINGTON (AP) _ Fidelity Investments' report of wrong mutual fund prices last week underscores the problems of an outdated system of transmitting fund prices to the public, industry officials say.

The pricing system has failed to keep pace with the industry's dramatic growth and complexity. That in turn has led to frequent errors and omissions in mutual fund tables printed in newspapers.

''When you're dealing with very complex data and you have to crunch it in a short amount of time, you're not always going to bat 1.000,'' said Jon Teall, a spokesman for Lipper Analytical Services.

The focus on reporting of mutual fund prices came after Fidelity Investments admitted this week it provided day-old price listings for 150 of its 208 mutual funds on on Friday, June 17, which led to errors in mutual fund tables printed in last weekend's newspapers. Fidelity said an employee wrongly relayed day-old prices after the day's calculations were snarled by a software error.

The system of reporting mutual fund prices to newspapers is prone to errors due to a complex number of transactions squeezed into a short time span each day.

The process starts after the bond market closes at 3 p.m. and the stock market closes at 4 p.m. The funds or companies hired by funds gather closing securities prices and start crunching formulas to arrive at a fund's net asset value - the value of a fund's securities portfolio, minus its liabilities, divided by the number of outstanding shares.

Prices of less complex funds - generally those only with U.S. stocks and bonds - can be available as early as 4:30 p.m. The more complicated funds with foreign stocks or exotic mortgage securities have a tougher time calculating the net asset value in time for a 5:30 p.m. EDT transmission deadline to the National Association of Securities Dealers.

The NASD, the industry's self policing body, gathers this information, performs a quick check for errors, and then transmits it within a half-hour in one large batch to vendors such as Lipper Analytical Services, Tribune Media Services, and news organizations such as The Associated Press.

These groups do their own analysis, and newspapers begin receiving their mutual fund tables between 6 p.m. to 6:15 p.m.

This quick succession of steps can lead to errors: Lipper Analytical estimated that of the 3,500 funds which report prices daily, at least 30 funds correct errors from the previous day's transmissions. And at least 20 funds miss the 5:30 p.m. deadline and don't transmit price.

Tim O'Leary, a vice president at Bank of Boston, said that each day, pricing questions arise about 5 percent of his funds. He has about 10 minutes to investigate before the 5:30 p.m. deadline.

''It can get very touchy and hairy,'' he said.

To improve accuracy, some in the industry advocate pushing back the reporting deadline to 6 p.m. to permit additional review time. Major newspapers, however, say such an extension will complicate production schedules.

One key bottleneck is getting the pricing information to the NASD, industry officials say. After calculating the fund prices on their computers, the funds turn around and manually type in the net asset values into NASD computer terminals.

''Some of their technology is pretty stable and very reliable, but it's old,'' said John O'Neal, vice president of DST Systems of Kansas City, a leading mutual fund pricing service.

James M. Kennedy, The Associated Press business news editor who oversees the wire service's stock and mutual fund tables, said the current reporting system ''may have been adequate when there were a few hundred funds to follow.''

''But in a world of 3,500 funds, and growing, it doesn't meet the needs of the investing public,'' Kennedy said. ''And I believe it promotes errors and omissions as funds hurry to meet the single reporting deadline every night.''

NASD spokesman James Spellman said improvements are on the way. Spurred by the Fidelity case, NASD chairman Joseph H. Hardiman is pushing for a new method to collect fund prices when they're calculated and passing that information on to the vendors and news organizations, Spellman said.

Under this approach, the newspapers would receive a series of fund tables, the earlier versions containing the easiest to price funds, with the more difficult funds added in later versions.

''We're looking to this approach,'' Spellman said Friday. The NASD also will be improving its computer systems as part of a general overhaul of its technology, he said.