Ahead of Thursday's vote, the Survation poll for ITV's Good Morning Britain put Jill Mortimer of the Conservatives on 50 per cent - 17 points ahead of Labour's candidate in a seat it has held since it was created in 1974.
Mrs Mortimer, who lives near Thirsk and is described as a farmer and a district councillor on Hambleton council in North Yorkshire, has had heavyweight support from senior Conservatives during the campaign.
Prime Minister Boris Johnson visited Hartlepool this weekend for the second time since the by-election was announced following the resignation of Labour's Mike Hill as MP for the north east constituency.
Thelma Walker, who served as Labour MP for Colne Valley in West Yorkshire for two years and left the party last year, will also be bidding to win the seat for the newly-formed Northern Independence Party. The latest Survation poll - which interviewed 517 Hartlepool residents aged 18 and over by telephone between April 23 and 29 - put her on six per cent in third place.
Labour’s candidate Dr Paul Williams is described by leader Sir Keir Starmer as "a tireless champion for the great town of Hartlepool".
Sir Keir, who has visited the constituency three times in the course of the by-election, said he hopes Labour will not lose another seat in the party's so-called "red wall".
However he acknowledged that the party still has a "mountain to climb" after the devastating defeat under Jeremy Corbyn in the 2019 general election if it is to get back to a position where it can regain power.
"I hope we won't lose Hartlepool. We are fighting for every vote there. I know that every vote has to be earned," Sir Keir told BBC Radio 4's Today programme.
"I said on the day that I was elected (Labour leader) that it was a mountain to climb. It is, we are climbing it and I've got a burning desire to build a better future for our country.
"I don't think anybody realistically thought that it was possible to turn the Labour Party round from the worst general election result since 1935 to a position to win the next general election within a period of one year. It was always going to take longer than that."
With voting taking place across Great Britain on Thursday - including for English councils, the Scottish Parliament and the Welsh Senedd - Sir Keir acknowledged he is facing his first major electoral test.
"I take full responsibility for the results, just as I take full responsibility for everything that happens in the Labour Party under my leadership," he said.
Since the turn of the year, the polls nationally have consistently shown the Conservatives ahead - although there was some tightening over the weekend, suggesting the charges of "sleaze" may be beginning to cut through.
Hartlepool is a seat long held by Labour and the party fought off a strong Conservative and Brexit Party challenge at the 2019 general election, although their majority was reduced to just under 3,600, down from 7,650 in 2017.
Labour have held Hartlepool since the constituency was created in 1974. Prior to that, 'The Hartlepools' has mostly been held by Labour since the Second World War apart from five years between 1959 and 1964 when it was Conservative.