National Party leader Frederik de Klerk summoned the ruling party's highest policy-making body Monday, bidding for overwhelming support in his power struggle with President Pieter W. Botha.

State-run government radio said the week ahead would be one of "decisive importance" following the 73-year-old Botha's announcement Sunday night that he was resuming his duties Wednesday and would not resign to meet party demands for an early general election."I'm not an old man clinging to power," said Botha, who suffered a stroke on Jan. 18 and swiftly turned over presidential duties to Constitutional Affairs Minister Chris Heunis, a loyal ally in a party that has become extraordinarily hostile to his return.

"I'm clinging to good order and I'm clinging to the idea of good discipline," Botha said.

De Klerk, who said the party would give "urgent attention" to Botha's announcement, summoned a meeting of the policy-formulating federal council Monday evening in Cape Town, Radio South Africa said. A parliamentary caucus, not scheduled to be held until Thursday, was rescheduled for immediately after the federal council meeting.

Caucus spokesman Con Botha said de Klerk would be attempting to get a "wider endorsement" for his position that the party leader must also be the head of government and the "whole question of division of power."

Nearly two weeks after suffering the stroke, Botha surrendered the party leadership in what he characterized as a long-contemplated move to put the presidency above party politics and allow more time to pursue his racial reform program.

De Klerk was elected the new party leader and began consolidating his personal power base to challenge Botha's decision to split the nation's two most powerful positions.

In his first television interview, Botha told the state-run South African Broadcasting Corp. that unnamed forces were "seeking to exploit an unfortunate situation" and said he wanted to meet with the ruling party caucus.

Botha's second five-year term would expire in September but is constitutionally extensible until the term of parliament ends in March 1990. He said he hoped to work with de Klerk in a "spirit of good will" but noted de Klerk was "being misused by some people."

"It must be obvious to every member of the public that there are forces in this country seeking to exploit an unfortunate situation to sow political confusion, and I am convinced that responsible people in and out of parliament will not be party to this."

The interview was conducted at Botha's residence in the area of Wilderness, along the southern coast outside Cape Town, where he has spent much of his time recovering from what was described as a "mild stroke."