An Arlington cable televison project to expand the number of channels, which has caused numerous outages and interruptions, will be finished in about six weeks, according to an official of the cable firm.

"It's almost over; we're as anxious to have this over as you are," Metrocable President John D. Evans told the Arlington County Board Saturday. He added that there will be a "brief" shakedown period after completion of the construction.

The channel expansion project will increase the number of channels available to subscribers from 36 to 54. It is far ahead of schedule but the replacement of major system components has caused service interruptions to occur over a longer period of time than expected, Evans said.

Work in North Arlington is almost finished and, in response to a county request, the firm will send letters to notify subscribers in South Arlington about the ongoing work, Evans said.

The project has "been painful for the community," and "we appreciate the community's indulgence," he said.

In recent months, the county has received more complaints about Metrocable than at any point in the history of the franchise, County Board Chairman John G. Milliken said. Officials of the firm insist that the number of complaints is still only a small fraction of the estimated 37,000 subscribers.

"Citizens are understandably upset about reception difficulties and frequent outages," said Milliken, reading from a prepared statement.

In addition to asking that the cable firm mail notices about the construction work to subscribers, the county has assigned staff members to handle complaints and has hired a consultant to advise on ways interruptions can be minimized during construction, he said.

A citizens committee has been appointed by the county manager to review cable service and make recommendations, he said.

Milliken said later that he also has asked Metrocable officials to consider giving consumers a rebate or partial refund to compensate them for the problems. The company's franchise agreement with the county requires refunds if an outage exceeds 24 hours and is the fault of the cable firm.

"My impression is that people are just as inconvenienced by periodic outages as a total blackout," he said. Metrocable officials have said they are considering requests for refunds on an individual basis, Milliken said.

Some residents have suggested that the county replace Metrocable with another company.

Milliken said he does not believe Arlington has the legal right to revoke Metrocable's franchise and that replacing the firm now "would be cutting off one's nose to spite one's face." The county last year extended Metrocable's franchise to the year 2000 after the firm agreed to expand the system's channel capacity.

"It's going to be tough" while upgrade work is in progress. But when that is over "we will all be better off," Milliken said.