Nigeria has launched a diplomatic campaign to gain the backing of western creditors for its recent economic reforms, including a controverial decision to limit annual repayment on its $17 billion foreign debt and to bypass the International Monetary Fund, according to a top Nigerian official.

The strategy, spelled out here by Nigerian Minister of External Affairs Bolaji Akinyemi, aims at breaking the "dictatorial" IMF hold over many economically troubled Third World nations that have been unwilling to meet the organization's stringent demands for economic reforms and unable to meet their foreign debt obligations.

The success of the Nigerian strategy of seeking to deal directly with its western creditors, without first gaining IMF approval of its economic reforms, could have a major impact on the overall Third World debt issue.

Nigeria decided last month to forgo a $2.5 billion IMF standby loan. Early this month it unilaterally proclaimed a ceiling on the amount it is willing to set aside this year to service its debt equal to no more than 30 percent of its foreign exchange earnings.

The Nigerian foreign minister said in an interivew with Washington Post journalists during a visit here this week that Nigeria intended to urge other Third World nations to follow Nigeria's lead at a special U.N. General Assembly meeting in May on Africa's economic crisis.

Akinyemi, who met Monday with Secretary of State George P. Shultz and earlier with British Prime Minister Margaret Thatcher in London, said both western leaders had clearly endorsed his government's recent reforms. He expressed confidence that Nigeria's creditors would now agree to reschedule its debts.

U.S. and British officials quickly denied this, however, saying neither government had changed its position on the need for IMF approval of the recent Nigerian economic reforms, although both endorsed the reforms generally.

The two governments, said a U.S. official, "have reiterated their position that they cannot reschedule Nigeria's debts without an IMF agreement."

A British official gave only a slightly different reply, saying Britain would insist on "some form of endorsement" by the IMF of Nigeria's economic reform measures before it would support another rescheduling of Nigeria's debts.

Nonetheless, Akinyemi said that it was his "reading" that Nigeria's creditors, represented by the so-called Paris Club, were "prepared to play ball with us."

"Creditors may not like the idea of a country unilaterally setting a percentage, but at the same time, to use the American phraseology, we've made an offer they can't refuse," he said, referring to the decision to limit its debt repayment to 30 percent of export earnings.

A spokesman for the Paris Club of western creditors said in Paris that officials of the group had agreed to hold "conversations" with Akinyemi on Nigeria's debt problem later this week. But he said the group's policy still insists on prior IMF approval of any debtor country's reform program before holding debt rescheduling "negotiations."

Following Akinyemi's meeting with Shultz, the State Department put out a carefully worded statement of support for the Nigerian reforms and overall approach to its debt problem. While continuing to insist the IMF could play "a useful role" in Nigeria, it commended Nigeria for instituting its reforms and said, "Each country must decide for itself the ways in which it will try to solve its economic problems."