LONDON (Reuters) - The controversial home information packs scheme is to be extended to all homes from next month, the government said on Thursday.

All property owners will have to offer potential buyers a home information pack (HIP), which includes legal documents and a certificate rating energy efficiency, from December 14.

The full HIPs roll-out was delayed because not enough people had been trained as energy assessors. The first phase started in August with the introduction of HIPs for houses with four bedrooms or more.

The government argues HIPs are needed to cut delays in home buying while the certificates will promote energy efficiency, but they have met with opposition because of their cost, and critics also say they make it more complicated to sell property.

The Royal Institution of Chartered Surveyors said HIPs had already led to the disappearance of a large proportion of an estimated 20 percent of speculative sellers that help keep the property market moving and warned the full rollout would hit first-time buyers.

"With prospective buyers and sellers currently taking a 'wait and see' approach to moving, activity in the housing market is grinding to a halt," spokesman Jeremy Leaf said.

"The housing minister needs to understand that rolling HIPs out to one and two bed properties could find first-time-buyers caught between a rock and a hard place as accessibility to the market would go off the scale."

But the government said the scheme was helping to save money.

"HIPs and EPCs (energy performance certificates) are already helping consumers to save hundreds of pounds off their fuel bills and are cutting search costs too," said housing minister Yvette Cooper.

Sellers whose homes score poor energy ratings of F or G (currently around a fifth of all homes) will be offered grants to make their properties more energy-efficient.

HIPs are currently taking an average of seven to ten days to produce and costing sellers around 300-350 pounds, according to the government.

Jeff Smith, chief executive of HIP Payment Services, said the announcement would be greeted with relief from the industry.

"With HIPs fully rolled out across the market they will finally be able to bring about the many benefits they were initially designed to achieve -- a faster, more transparent process which will aid a more informed buying decision," he said.