Liz Truss’s plans to legislate for a £100bn package of help with energy bills will not be affected by 10 days of national mourning for the Queen, despite parliament being cancelled for the next week, Downing Street has said.

The government is postponing most business until after the Queen’s funeral, but Truss’s team needs to implement the package before the energy price rise that is due to come into force on 1 October.

Parliament is unlikely to return until after the Queen’s funeral, with the earliest possible dates being 19 or 20 September. However, it is due to break up again on 22 September for its party conference recess, and Truss is supposed to be in New York for the UN general assembly for part of that week.

On Friday, Downing Street said plans would be put in place to ensure the support package was made available in time, and suggested that legislation would not be needed for the £2,500 cap on average bills to be put in place.

“The public should be reassured that the energy price guarantee will be in place for households from 1 October, as planned,” Truss’s official spokesperson said.

“We’re implementing that guarantee initially through private contracts with suppliers rather than through legislation, so this mourning period doesn’t impact that introduction.

“We’re working urgently now on the wider aspects of the policy to ensure it can be delivered. As it stands, we do not believe the mourning period would impact on delivery of the policy, neither do we think it requires any sort of legislative moments during the mourning period.

“We will be working with the Speaker to introduce any legislation that is required for as soon as possible after the mourning period concludes.”

With ministers holding back from outlining further details during the mourning period, energy suppliers are expected to contact customers before 1 October to explain how the announcement affects them.

Truss also announced an immediate lifting of the fracking ban in England this week, despite the Conservative manifesto promising not to do so unless it was scientifically proven to be safe amid concerns over earthquakes.

However, a British Geological Survey review into the safety of extracting shale gas was postponed from its scheduled publication on Thursday. Downing Street said this would now not be published until after the mourning period. A No 10 spokesperson said it would come “as soon as that period has concluded”.

The party conference season has already been affected by the national mourning, as the Trades Union Congress conference due to take place in Brighton next week has been postponed.

The Liberal Democrats conference is also hanging in the balance as that is scheduled for the week afterwards, potentially clashing with the Queen’s funeral, which is likely to be on Sunday 18 or Monday 19 September. Party sources suggested it was unlikely to be delayed until another time but could be curtailed or cancelled.

The Labour conference, which is due to start on Sunday 25 September in Liverpool, is thought to be very likely to go ahead.

One Tory source put the chances of the Conservative party conference going ahead in Birmingham from Sunday 2 October at 85-90%, with a decision “in the next few days”.

Conversations between the whips of the parties have taken place on the possibility of cancellation of the entire season, with one source saying the Tories seemed keenest on the idea of postponement, but that there had been no agreement and ultimately the main two parties were expected to proceed.