PORTLAND – The Portland Press Herald and Maine Sunday Telegram plans to lay off workers due to declining advertising revenue and the rising cost of newsprint, the company said Wednesday.

The company already has put a number of cost-cutting measures in place, but has reached the point where layoffs are unavoidable, said Jean H. Eichenbaum, vice president and general manager.

“Our revenues are both significantly less than we had budgeted and less than we brought in last year, so we have to make adjustments,” Eichenbaum said.

The paper’s 570 workers received a written statement along with their paychecks on plans to reduce the work force.

Advertising revenue has dropped as businesses have cut costs in the weakening economy. At the same time, newsprint – the paper product newspapers use – is costing the company about 20 percent more this year, Eichenbaum said.

She said the first layoffs would come from areas where workloads have been reduced by declining advertising volume. Company officials will analyze other departments, though most areas likely will be affected.

The timing and number of layoffs is uncertain. The company wants to make sure it makes the right decisions, Eichenbaum said. “We take it very seriously,” she said.

Eichenbaum said the company also may offer early retirement incentives and employee buyouts, which would reduce the number of layoffs. About 400 of the newspaper’s workers are full time.

Joanne Lannin, president of the Portland Newspaper Guild, which represents about 300 workers, said the union would like to see early retirement or buyout offers.

“We’ll be overseeing it to make sure they follow the contract [with the layoffs] and with any incentive programs they might offer down the road,” said Lannin, a features reporter.

The Seattle Times, the parent company of the Press Herald and Sunday Telegram, also has cut staff.