The debate over whether to extend the city's rent control law that expires April 30 began this week and promises to be, as in the past, one of the most crucial issues to come before the council.

On Tuesday, City Council Chairman David A. Clarke introduced a bill that is similar to the current rent control law and would extend its provisions to 1989. He said the bill is intended "to demonstrate a commitment to the continuation of rent control" and to begin council action.

"Rent control is very important to many of our constituents, and we do not have much time left," Clarke said. "We must get started."

In Washington, where nearly three out of four residents are tenants, rent control is always one of the most controversial issues on which the City Council must vote. Landlords, property owners and developers are outspoken opponents of the law, which they say unfairly limits their ability to collect rents and to raise enough money to maintain their properties as decent and safe housing.

Tenants fear that without the law rents could rise drastically.

Under current law, rent increases for most apartments are based on the consumer price index, and landlords can raise rents only once a year.

Although council members said they are certain that a majority would not vote to repeal rent control, they expect a great deal of debate involving how long a new extension should be, on how to compute rent increases and on removing vacant units from coverage by the law.

The council needs to pass new rent control legislation by next month so that the new bill can complete the mandatory 30-day congressional review period and still meet the April 30 deadline, Clarke said. He added that he does not want the council to get into a position where it has to introduce emergency legislation to extend the old law or implement the new one.

Five council members sponsored Clarke's bill but at least two others say they plan to introduce their own bills.

Council member John Ray (D-At Large), chairman of the council's consumer affairs committee, which will oversee all the bills and report out one to the council, said he plans to introduce his legislation next week.

Ray said that he views Clarke's bill as a political statement about his position on rent control rather than as an attempt to get the issue before the council.

"It rent control is going to be very controversial," Ray said. "It is one of those issues, from a political standpoint, that is easy to put into effect but difficult to make changes to."

Ray, who would say only that his bill would be be "fairly comprehensive," added that rent control was not the answer to the District's housing problems.

"Rent control, in and of itself, is not the cause either," Ray said. "One thing for sure, we can't get rid of it overnight. But I'm taking the approach that we have to look for something to start phasing it out."

Ray said he sees no problem with adopting an emergency rent control law if necessary.

City Council member Betty Ann Kane (D-At Large), who said she, too, plans to introduce a rent control bill, said that she is convinced that the law has had a negative effect on housing in the District.