WARSAW, Poland (AP) _ Days after the prime minister cut the ribbon to inaugurate a modern international air terminal for Poland, a minor official has decreed it cannot open.

The $189 million Okecie II International Airport, one of the largest state investment projects in Poland, was supposed to welcome its first arrivals this week and swing into full operation in early July.

But instead of coming into a spacious five-level and fully automated airport, travelers are still crowding into the old Okecie terminal, with slow- moving passport lines and an often-broken luggage conveyor.

Michal Sosnkowski, provincial inspector for environmental protection, said his decision was justified by the new airport's lack of systems to reduce noise and prevent pollution of a nearby water canal.

He said it is irrelevant that the present airport, next door, does not have them either.

''The terminal cannot be opened without my approval and my decision has to be respected,'' Sosnkowski said in a telephone interview.

Asked why he issued the decision two days after the airport's ceremonial opening on June 17, Sosnkowski said his office was set up only in December and ''it was the fastest I could act.''

''The news was shocking for us,'' said Danuta Bajkowska, head of the organizational department at the state airport authority. ''The terminal is beautiful and it is waiting for passengers.''

If authorities accept Sosnkowski's decision, the new airport would remain closed for three more years, she added. ''This is simply sick. This is doing harm to passengers and damage to Poland's image,'' Bajkowska said.

The state airport authority has protested Sosnkowski's decision, but the terminal remains closed pending a decision by the country's chief environmental inspector. The final verdict is expected within days.

The airport building schedule approved by the government and environmental inspectors in 1989 includes the devices demanded by Sosnkowski, Bajkowska said, but they were to be completed within the next five years.

She said the airport lacked funds to install the systems immediately, and they were to be paid for out of the new airport's earnings.