Former President Donald Trump’s favorability rating has fallen to one of the lowest points since he left the White House, according to a new poll. ​

Just 34% of registered voters have a positive view of the former president, compared to 54% who have an unfavorable view, giving him a -20 net negative rating, an NBC News poll released Sunday found. ​

That net score is down slightly from last month when it was 54% negative and 36% positive, and May, when it was 36% positive and 51% negative. ​

His rating hit its lowest mark in April 2021 at 55% negative and 32% positive for a -23 net negative. ​

Trump’s net negative rating puts him below the Republican Party (33% positive, 48% negative), the Democratic Party (37% positive, 47% negative) and President Biden (42% positive, 47% negative).

Florida Gov. Ron DeSantis, who is a likely challenger if Trump mounts a 2024 presidential bid, has a -2 net rating (- 31% positive, 33% negative).

Trump spokesman Taylor Budowich told The Post that although Trump “has not yet made an announcement about his 2024 intentions, polling clearly shows him in a dominant position in both the Republican Primary and General Election.”

Budowich pointed to a Harvard Harris poll conducted this month that showed Trump with 59% support in a hypothetical Republican primary against DeSantis (17%), former Vice President Mike Pence (9%) and former South Carolina Gov. Nikki Haley (2%), among other potential rivals.

“Activist pollsters often try to cook up polls to push a false narrative, but the reality is President Trump’s strength and popularity are fueling the Republicans’ strength into November and beyond,” Budowich said.

The RealClearPolitics average of recent national polls shows Trump would beat Biden in a general election rematch, 44.5% to 43.8%.

The new NBC poll found that California Gov. Gavin Newsom, a leading potential Democratic candidate if Biden steps aside in 2024, has a 18% positive, 33% negative rating for a -15 net negative rating.

But despite the low numbers tallied by NBC for Trump and the Republican Party with 50 days to go before November’s midterm elections, registered voters are split 46% to 46% over which political party they want to see control Congress. 

That tie is basically unchanged from last month’s poll that gave Republicans a 2 percentage-point edge — still within the margin of error. 

The poll shows that Republican voters pick border security (50%), the economy (47%), immigration (46%) and crime (45%) as their top issues, while Democrats choose abortion (47%), health care (44%), education (40%) and protecting democracy (40%) as their most pressing issues. 

The poll surveyed 1,000 registered voters between Sept. 9 and 13.

It has a plus/minus 3.1 percentage-point margin of error.