NEW YORK (AP) _ The Discovery Channel is dropping the weeknight ''World Monitor'' news program that it has shown since the program began in September 1988, the cable network said Wednesday.

The change is effective Jan. 6. After that, the series will appear on the new, far smaller Monitor Channel, which like the program is owned by the Christian Science Church.

Discovery's action wasn't unexpected.

The network, which serves 56 million homes, had been considering whether to drop the series after its anchorman, veteran newsman John Hart, resigned without a public explanation almost two weeks ago.

Hart's permanent replacement, former NBC correspondent and ''Today'' news anchor John Palmer, will start work on Jan. 6. The Monitor Channel earlier had said he would begin Monday.

In an interview earlier this month, Discovery chairman John Hendricks said Hart's presence on ''World Monitor'' was a ''key element'' in Discovery's initial decision to sign a six-year contract for the show.

But Hart's departure wasn't the reason Discovery opted to drop the program, said Eric McLamb, a spokesman for the Maryland-based network.

He said Hart's action was ''just one element'' in Discovery's decision to re-evaluate the show and, finally, to drop it.

Discovery's programming largely consists of documentaries on various topics. And Hendricks said in a statement that the company now believes more in-depth, multipart documentaries would best serve its viewers.

The time period ''World Monitor'' has held on Discovery will be filled by ''Discovery Showcase,'' a series of documentaries on technology, nature, history and world exploration.

Although Hart, 59, has yet to say why he quit, one TV executive familiar with the situation has said Hart just wanted to take life easier.