The European Commission on Thursday backed new aviation security rules that will restrict the amount of liquids passengers can take on board planes.

The rules, expected to come into force in early November, allow passengers to carry on toiletry items such as toothpaste, contact lens solution and perfume but not large drink containers, except those purchased after security checks.

Size limits for carry-on bags will enter into force in six months.

The rules were proposed last week by experts from EU member states to unify security measures across the 25 nation bloc.

Authorities in London said in August they had foiled a plot to bomb flights to the United States using liquid explosives.

Passengers will be allowed to bring on board one re-sealable plastic bag of a maximum size of 1 litre in which liquid items could be stored. Liquids would have to fit into containers that were 100 ml or smaller.

Certain exceptions will apply for medicines, baby food and other dietary needs, the Commission said.

Carry-on bags will be limited to 56 cm by 45 cm by 25 cm.

"The new regulation will plug a gap in our defences by restricting the liquids that passengers can carry past screening points and on board aircraft," said EU Transport Commissioner Jacques Barrot in a statement.

"It will apply to all departing flights in order to protect people everywhere in the (EU)."

Exemptions on the size of hand luggage will be possible for items such as musical instruments and cameras.