The Idaho Public Utilities Commission has postponed a telephone rate increase for US WEST Communications customers scheduled for Sunday at the company's request.

The PUC had authorized an increase of between 57 cents and 67 cents per month for residential customers and between $1.41 and $1.68 per month for business customers.But last week, US WEST proposed to give up the increase and other charges for three years if the commission drops an investigation into the company's earnings.

Without passing on the merits of the company's proposal, the commission said it would postpone the increase to avoid rate fluctuations. A ruling on the application is not expected for several weeks.

Meanwhile, beginning Sunday, US WEST will be allowed to reduce the number of free directory assistance calls from three per month to two. At 30 cents a call, that will mean $200,000 a year in revenue for the company, the commission said.