KAILUA-KONA, Hawaii (Reuters) - Hawaii residents were urged on Wednesday to stay clear of beaches and avoid swimming in the ocean after a tsunami advisory was issued for the state following an 8.2 magnitude earthquake that struck off the coast of Chile.

The advisory from the Pacific Tsunami Warning Center cautioned that possible sea level changes and strong currents could pose a danger to swimmers and boaters, although experts said they did not expect evacuations to be ordered.

"We're sure the waves are not going to be large enough to cause any flooding," Gerard Fryer, senior geophysicist for the center, told reporters. "However, we're worried there may be dangerous currents so we want people off the beach and out of the water."

The advisory, issued late Tuesday after the quake struck off Chile's northern coast, is less significant than a tsunami warning, which would be prompted by expectations of widespread flooding.

The initial wave from the earthquake is expected to reach Hawaii at 3:24 a.m. local time (0924 EDT).

Fryer said the real concern was strong currents at beaches and marinas.

"Occasionally you get a larger wave so it sweeps up the beach or something," he said. "If you're not ready for it you can get into difficulty, and if you're in the water you can get banged about."

The advisory for Hawaii will last until around 6 a.m. or 7 a.m. local time on Wednesday, Fryer said.

In Chile, six people have died following the massive quake that struck the north of the Andean country, Interior Minister Rodrigo Penailillo said.

The Pacific Tsunami Warning Center said the quake generated a large tsunami with the biggest wave reported at more than 7 feet. The Chilean navy said the first big wave hit the country's coast within 45 minutes of the earthquake.

(Reporting by Karin Stanton in Kailua-Kona and Victoria Cavaliere in New York; Editing by Nick Zieminski)