The UN said the survivors had been stranded in mountains and called the incidents extremely disturbing.
Since then the UN and dozens of other organisations have remained involved in the emergency relief work.
However, heavy rain and snowfall early this week created new landslides, leaving thousands of people stranded in mountainous regions.
United Nations deputy humanitarian coordinator in Pakistan, Larry Hollingworth, said the two helicopter incidents were regrettable.
He said in both cases the people were transported to safer places and no-one was detained.
The BBC's Zaffar Abbas in Islamabad says these are thought to be the first such incidents since the earthquake.
A senior UN official told the BBC that in one case about 20 people forced their way onto a UN helicopter as it was about to leave the town of Banamula, after dropping food supplies.
He said some of the people were rowdy and misbehaved with the UN staff. Eventually the helicopter crew had no choice but to fly them to Muzaffarabad.
In the second case, about 35 people stormed a UN helicopter and had to be evacuated to the town of Abbottabad, although it was not clear where the incident started.
The UN official said even though no-one was seriously injured, the two incidents were extremely disturbing.
Mr Hollingworth said the UN was in touch with the Pakistani military and civilian authorities and the matter was being investigated.
"I presume they were coming down from the mountains and basically wanted out. It's very cold there," Mr Hollingworth said.
He could not confirm reports that one UN staff member had been punched.
The relief effort is still a huge operation, with helicopters vital in transporting supplies.
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