A Northland man will think twice before washing his hands over the side of his boat after seeing a shark leap out of the water to bite his berley bag last week.

Richard Parker was fishing off Whangarei Heads on Thursday, only 30m from shore, when he had his close encounter.

"I was just sitting there dreaming in my boat, when a white belly came shooting up out of the depths," Mr Parker said.

"It totally left the water and splashed me as it came back down."

The shark, which Mr Parker said was as big as he was, grabbed his berley bag with bait in it to attract fish, shook it violently and ripped it in two.

"It happened so quickly and so spectacularly."

Mr Parker said he had been out fishing about twice a week and the water was teeming with fish and sharks this month.

"The sharks have come in very early. There's a lot of action happening [under water]."

He had no doubt that the sharks were attracted by the warm, clear water.

"I'll think twice about washing my hands over the side because the water is so clear. You could lose your hands," he said.

"It took me totally by surprise."