A survey, conducted by Kantar TNS, showing an extension of Høyre’s lead means there could potentially be a majority for the centre-right parliamentary bloc after the election on 11 September.
The four parties in the Conservative bloc would get 87 seats in parliament, if the poll is correct.
The left-wing parties would get 78 seat.
According to TV2’s poll, the conservatives and the labour party are now level.
Høyre are up 1.1 points in the poll, while AP declined by one point.
The results leave both parties with 26.1 points.
The poll is disastrous news for AP, who are usually Norway’s biggest party.
This is the lowest response the Labour party have had since summer 2013.
Leader for AP Jonas Gahr Støre told Aftenposten: “Many of the people who voted for us in 2013 are on the fence.
“These voters need to be woken up.”
Two-thirds of the respondents say they believe Høyre’s Erna Solberg, who is the current prime minister in Norway, will remain in power.
Just one-third, meanwhile, believe Labour’s Jonas Gahr Støre will be the new leader.
Ms Solberg believes the latest poll will see an increased turnout.
She said: “People will now make an extra effort to make sure this becomes a reality.”
Mr Gahr Støre told TV2 that he would have liked to have seen a better result, but played down the worries.
He said: “It is what happens on 11 September that counts. AP is mobilised. We are campaigning and we believe in what we do. I think many people want change.”