The government has insisted it will press ahead with plans for new corporate killing laws.
Charges against Railtrack over Hatfield were dropped
But the reforms are unlikely to be pushed through this year, as campaigners had hoped.
The Home Office says it will publish a draft bill by the end of November but there is no guarantee it will be included the Queen's Speech.
A spokesman said it had taken longer than expected to draw up the plans as it was a very complex area of law.
About 3,000 workers have died in work-related incidents in the past 10 years.
The renewed pledge comes days after corporate manslaughter charges against Railtrack over the Hatfield train crash were dropped.
Under the current law, firms can be found guilty of manslaughter only if at least one person named as the "guiding mind" is convicted.
This means that large companies, where lines of responsibility are harder to establish, usually escape prosecution.
The unions say this also prevents prosecutions where there is systemic management failure.
A Home Office spokesman told BBC News Online: "We are hoping to publish a draft bill before the end of November.
"That's what we have announced in terms of the draft bill and we remain firmly committed to that.
"It does involve very complex areas of law and there are questions which still need to be resolved.
"It is a very difficult area in terms of framing the legislation.
"It has taken longer than we originally expected but the critical thing is that we get it right in terms of the accountability of the companies and how the offence works as well," the spokesman said.
He added that there was no guarantee it would be included in the Queen's Speech, in which the legislative programme for the next parliamentary session is laid out.
"It will depend on what else is included," he said.
Next year's legislative programme is likely to be squeezed by the likelihood of a general election.
But the government has been saying it would bring forward plans for a corporate manslaughter offence since 1997 - it has been a Labour manifesto commitment since the 2001 election.
Hugh Robertson, head of health and safety at the Trades Union Congress, which has been pushing for the law, said the government had been dealing with these "complex issues" since 1997.
"We genuinely think the government does want to introduce this. There's a genuine belief that they want to do it but what there isn't is the will to get it out.
"The reality is that if they haven't resolved these [legal] issues now, then how can they say they will resolve them in the next two months or so.
"If they cannot resolve them there are plenty of other people who can. What we need to see is a draft bill.
Plans to make individuals potentially liable under a corporate manslaughter law have already been dropped by the government.
Instead the new offence is likely to concentrate on threatening big firms with the stigma of being convicted of a criminal offence.