LONDON (Reuters) - The coalition government said on Friday it will introduce temporary bans on legal drugs that could be harmful to users.

A proposed new law will allow authorities to react quickly as new substances emerge with 12-month bans while experts assess the drugs.

The move reflects public concern over the effects of “legal highs” such as the drug mephedrone which was banned in April.

“The drugs market is changing and we need to adapt current laws to allow us to act more quickly,” Crime Prevention Minister James Brokenshire said in a statement.

“The temporary ban allows us to act straight away to stop new substances gaining a foothold in the market and help us tackle unscrupulous drug dealers trying to get round the law by peddling dangerous chemicals to young people,” he said.

Under the planned legislation, authorities would be able to ban substances temporarily following an initial consideration by the Advisory Council on the Misuse of Drugs (ACMD).

The ACMD would then carry out a comprehensive review of the substance and advise whether it should be permanently banned.

Police would be able to confiscate suspect substances and the UK Border Agency could seize shipments entering the country.

The penalty for supplying a banned drug would be a maximum of 14 years in prison and an unlimited fine.

Possession of a temporarily banned substance for personal use would not be a criminal offence “to prevent the unnecessary criminalisation of young people,” the government said.

Subject to parliamentary approval, the system of temporary bans is expected to be introduced by the end of next year.