Strict rules for crematoria to limit mercury pollution caused when tooth fillings are vaporised have been announced by ministers.
Crematoria contribute 16% of the UK's mercury emissions
The industry has been told mercury filtering equipment must be fitted at crematoria by 2012 to halve emissions.
Exposure to the metal is linked to damage to the brain, nervous system and fertility with crematoria responsible for 16% of the UK's mercury pollution.
But the industry said it was an over-reaction and would lead to price rises.
Duncan McCallum, secretary of the Federation of British Cremation Authorities, said: "I think the industry feels it is a bit like using a sledgehammer to crack a nut. We are disappointed.
"We are not sure crematoria are such big contributors as the government says.
"The problem is that not all crematoria will be able to fit the equipment.
"The filters are quite large and some crematoria are in small buildings that are listed so it may not be possible to install them."
He also said the equipment, which costs £250,000, would be too expensive for some of the 650 crematoria in the UK.
However, he allayed fears crematoria would be forced to close - originally it was thought one in four would not be able to cope once the new rules came into place.
He said the industry was setting up a "trading scheme" which would allow crematoria without filters too buy credits off ones that do have them.
As the equipment reduces mercury emissions by up to 99% and the rules stipulate emissions must be halved, crematoria with the equipment will be able to make up the shortfall for crematoria without the filters.
And the National Association of Funeral Directors (NAFD) estimated it would add upto £100 to the price of cremation, which currently cost between £250 to £350.
Alan Slater, chief executive of the NAFD, said: "What concerns us is that bereaved families will have to bear the cost of this.
"Crematorium managers will pass the costs on but it is funeral directors who will have to address the issue with relatives."
However, the government defended the new rules, saying that unless action was taken mercury emissions would rise by two-thirds by 2020.
The government is committed to reducing mercury pollution under the UN Heavy Metals Protocol.
Restrictions on other industries have already helped reduce mercury emissions from 31.6 tonnes in 1990 to eight tonnes in 2002.
And Environment Minister Larry Whitty said: "By 2020, crematoria will be by far the biggest single contributor to mercury emissions in this country.
"Something must be done. Our decision - on which we consulted widely - strikes a balance between the concerns about cost to crematoria and the need to control emissions of a substance which can damage human health and the environment."