They will have powers to issue fixed penalties to anyone caught smoking in enclosed public spaces in Northern Ireland from April 30.

But they will also be required to fine business owners and local authorities who fail to stop smoking in premises that fall foul of the ban.

And that means, if someone is caught having a sneaky puff in a smoke-free bus shelter, its owner may be liable to pay a fine of £200.

Failure to cough up could lead to prosecution and a maximum fine on conviction of a whopping £2,500.

No Smoking signs will have to be displayed in all premises affected by the ban.

As a result, council bosses could face prosecution if a member of the public is caught lighting up in a bus shelter in which smoking is deemed illegal.

Bus shelters are classed as no-smoking premises under the legislation if they are "wholly or substantially" enclosed.

Many shelters in rural areas are the responsibility of local councils.

In other areas, particularly greater Belfast, marketing company Adshel supply shelters under contract to the DRD's Roads Service.

A spokeswoman for the DRD said: "Roads Service is aware that there are some enclosed bus shelters.

"We will put up signs in these shelters before April 30 stating it is against the law to smoke in them.

"Roads Service also plans to put up non-compulsory advisory non-smoking signs in all bus shelters."

It is expected that two environmental health officers will be appointed in each of the 26 local council areas to patrol all enclosed premises in order to enforce the smoke-free legislation.

Last night, smoking lobby group Forest branded the legislation relating to bus shelters as "madness".

A spokesman said: "This legislation was originally meant to ban smoking indoors, but with the inclusion of the likes of bus shelters it has crept outdoors.

"It's sheer madness and all commonsense has gone out the window."

A spokeswoman for the Department of Health said: "Bus shelters which are enclosed are covered by the legislation.

"Councils and Government departments are required to comply with the law, just like everyone else."