France's conservative government, under political pressure to show that it is dealing effectively with terrorism, announced today it was expelling four Libyan nationals.

Security Minister Robert Pandraud said that the Libyans were being expelled "because of actions likely to trouble public order." He refused to identify the Libyans, who were placed aboard a Libyan airliner for Tripoli, the Libyan capital, this evening.

It was the first such action since the U.S. bombing raid against Libya earlier this week. France expelled two members of the Libyan embassy, or "people's bureau," on April 5 after uncovering a plan to stage an attack on a U.S. consular office in Paris.

The latest expulsions coincided with a growing debate here over how to counter state-inspired terrorism. An opinion poll published this week showed that French citizens are almost equally divided over whether the Reagan administration was justified in its decision to bomb Libya following allegations of Libyan involvement in terrorist incidents.

The new government headed by Prime Minister Jacques Chirac promised a concerted campaign against terrrorism in coordination with France's major western allies after the narrow right-wing victory in last month's parliamentary elections. But France refused to grant a U.S. request for overflight rights to Libya for F111 bombers based in Britain.

The government's refusal to assist the U.S. bombing raid provoked criticism from some of its own supporters, notably members of the center-right Union for French Democracy who expressed outspoken support for the U.S. action. The party, founded by former president Valery Giscard d'Estaing, is also unhappy because of its failure to win key posts in Chirac's Cabinet, which is dominated by the neo-Gaullist Rally for the Republic (RPR).

Defending the government's action on terrorism, RPR Secretary General Jacques Toubon said today that France had given information to the Reagan administration about the planned attack on the U.S. Consulate here. He told journalists that France would sign a joint declaration on combating terrorism at the western economic summit in Tokyo next month.

In a radio interview today, Security Minister Pandraud also insisted that the government was fulfilling a promise to "terrorize the terrorists." He cited the arrest this morning of six alleged members of Direct Action, an extreme left-wing group that has claimed responsibility for the attempted murder of a French industrialist earlier this week.

"I am not like Jesus Christ. If you slap me, I will reply with two slaps," Pandraud said.

According to an opinion poll to be published in the weekly magazine Le Point next week, 55 percent of French citizens supported the government's decision to refuse overflight rights to U.S. airplanes against 26 percent who "disapproved."