Local residential telephone rates across America are due to go up twice in the coming months, but state utility consumer advocates are trying to head off the increases before they can take effect.

The National Association of State Utility Consumer Advocates wants the Federal Communications Commission to cancel increases scheduled for December and next April in the "line charge" added to residential phone bills.Their call is being heard by some members of Congress and the state utility commissioners, who at the very least want the FCC to take a second vote on the added charges before they take effect.

The increases - 60 cents per month on Dec. 1 and 30 cents on April 1, 1989 - were approved as part of a three-step boost in the monthly line charge that began with a 60-cent increase July 1, 1987. The monthly charge is already $2.60.

The FCC approved the increases in April 1987 as a way to further reduce long-distance rates and encourage large business users to stay on the public phone network.