Labour is looking to hold on to the so-called "red wall" seat and see off a challenge from the Conservative Party.
Dr Paul Williams, who was the MP for Stockton South from 2017 until 2019, is contesting the traditionally Labour-held seat after incumbent Mike Hill resigned in March amid sexual harassment allegations.
The Prime Minister may not know the value of the pound in his pocket, but we know you do
The labour leader, who is due to visit the North East constituency for a third time on Saturday, has accused the Conservatives of being "hopelessly distracted by sleaze and scandal" in the run-up to the vote.
He pledged to voters that a government under his leadership would always ensure that “taxpayers’ money is spent wisely” as he looked to keep Boris Johnson’s spending on renovations for his Downing Street flat in the spotlight.
Sir Keir said he is at Liberty Steel in Hartlepool because 'every vote has to be earned'
Sir Keir said: "Hartlepool needs a strong voice and Dr Paul Williams is that strong voice."
"What everybody has been saying to me what matters more than anything are jobs, jobs, jobs 'do you have a plan' and we've got a plan nationally for 400,000 jobs and Dr Paul has a plan for Hartlepool."
"This isn't about me, this is about Hartlepool and I want Hartlepool to have a strong voice, I want someone who is going to stick up for those communities."
Reports have suggested that the Conservative Party leader spent as much as £200,000 on the refurbishment of his No 11 living quarters, with the Opposition party calling on the Parliamentary Commissioner for Standards to investigate the Prime Minister’s conduct over the flat revamp.
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Separate probes by the Electoral Commission, the Cabinet Secretary and independent adviser on ministers’ interests Lord Geidt have already been announced.
Labour has also accused the Tories of handing out “crony” contracts worth billions of pounds to friends of the party during the coronavirus pandemic, leading Sir Keir to dub the Prime Minister “Major Sleaze”.
Writing in the Northern Echo, Sir Keir said: “Instead of tackling the issues that matter, the Conservative Party has become hopelessly distracted by sleaze and scandal. And it’s you and your family who feel the impact.
"At next week’s elections there is a very clear choice: Labour candidates who will be relentlessly focused on jobs, tackling crime and supporting your health.
"Or the same old Tories: sleaze, waste, one rule for them, and another for everyone else.
"I’ll be back in the North East today, in Durham and Hartlepool, making that argument.
"The Prime Minister may not know the value of the pound in his pocket, but we know you do.
"The least people should be able to expect from their government is that taxpayers’ money is spent wisely. Under my leadership, it will be."