In a statement released on Tuesday, the party said the Labour leader held a call with staff alongside the general secretary and announced plans to capitalise on promising leads over the Conservatives in recent polls.
Sir Keir Starmer is said to have told party employees that 'it is not the time for complacency or caution' and that long-planned changes to structures must be brought forward in light of the Conservative Party's 'implosion'.
Sir Keir Starmer is making changes to his party
Jacob King
"The Government's collapse has given us a huge chance. The instability means they could fall at any time. Because of that we need to get on an election footing straight away," staff are said to have been told by the Labour leader.
It is believed he urged the party to 'seize the opportunity we have and show the British people we are the party that can lead our country forward'.
As part of the changes, Sam White, who was appointed as chief of staff last summer, will leave his position.
Sir Keir paid tribute to Mr White, saying: "Sam has played an incredible role taking our operation to the next level. Under his leadership the team has become better and stronger."
He said that the merger meant that running the leader's office becomes a smaller role than Mr White signed up for "and we both agree as we're making this change, now is the right time to go".
Mr White said: "The next phase of the campaign needs a different structure, but we part very much as friends with the intent to work together again in the future. You'll find no greater champion for a Starmer government than me."
The new structure means policy and communications will move into Party HQ, reporting to general secretary David Evans.
Mr Evans is said to have made clear that no jobs are at risk as a result of the restructure.
On Monday, Kwasi Kwarteng brought forward the publication of his financial strategy and independent economic forecasts to Halloween.
Kwasi Kwarteng has brought forward his medium-term fiscal plan
Aaron Chown
Completing another U-turn, Mr Kwarteng agreed to set out his medium-term fiscal plan alongside Office for Budget Responsibility predictions on October 31 rather than November 23.
Earlier this month, the Chancellor backed down on his widely-criticised plans to scrap the top rate of income tax on earnings over £150,000 during the Conservative Party's conference in Birmingham.
Meanwhile, as MPs return to Parliament this week, Prime Minister Liz Truss is said to be launching a charm offensive to bridge the divides blighting her party.
Ms Truss is expected to hold policy lunches with groups of colleagues and address the 1922 committee of Conservative backbench MPs on Wednesday.
It comes amid an internal row over whether the government will decide to raise benefits in line with inflation.
Ministers have been considering whether to link an increase to earnings rather than the currently much higher measure of prices.