Four in five waste items found on beaches in 2021 were single-use plastics such as food and drinks containers.
Environmental charity Keep Northern Ireland Beautiful (KNIB), which compiles the Marine Litter Report, said the findings were very concerning.
It said plastics damage the environment, the economy and humans.
The report collects information about litter on beaches across the region, with four surveys completed throughout the year.
Observing 12 reference beaches around Northern Ireland, the report found an average 760 items recorded per 100 metres - roughly eight pieces of litter per step.
Short pieces of string, cord and rope were also found across all beaches, as well as 1,012 heavy-duty gloves - most commonly associated with fishing gear - which was double on 2020.
Chief executive of Keep Northern Ireland Beautiful Dr Ian Humphreys said when a person dropped a piece of litter, whether in town or on the beach, it often found its way out to sea.
"The erosion caused by waves will break down that plastic into smaller and smaller pieces, so if the piece of litter doesn't choke a turtle or strangle something in its early days, then it becomes microplastics and the research shows that it then goes in the food we eat.
"It comes up the food chain, it's in the water we drink, it's in the air we breath and recent research is now finding it in human blood," he said.
"It can't be good when our own pollution and litter is coming back to live inside us."
'Look at alternatives'
The Marine Litter Report, which is funded by the Department of Agriculture, Environment and Rural Affairs (DAERA), found the amount of litter had doubled since 2020, when a slight downward trend had been noted.
Increases in 2021 have been attributed in part to the lifting of Covid-19 restrictions, winter storms and people having less time to carry out clean-ups.
Dr Humphreys said the key problem was consumption habits.
"Single-use plastics are by far the biggest element in marine litter so that plastic, whether it's the plastic lid of a coffee cup, or the plastic lining of the coffee cup, the plastic in cigarettes or the polystyrene packaging of fish and chips, these are all things that we could look at alternatives to."
"The carrier bag levy that DAERA introduced was highly successful in driving down the use of single-use plastic bags and they are looking at a levy on coffee cups, which would hopefully move us to remember to bring our refill cup and remove that problem of having to use a single use plastic," Dr Humphreys said.
Survey volunteer Paul Moore
'You should be responsible for your own rubbish'
Paul Moore from Belfast has carried out surveys at Northern Ireland's beaches for the past decade and confirmed that single-use plastics, like food and drinks containers, make up most of the litter left behind.
"It's usually people having picnics or small walks and just dropping food wrappers behind them," he told BBC News NI.
"It's never horrific but there's also a lot of washed-up stuff, which is hard to recognise sometimes."
Mr Moore added that nature as well as people can wash items ashore, however, he urged people not to leave litter behind.
"It's human nature unfortunately, if somebody else is going to clear it up, they'll let them do it. You should be responsible for your own rubbish.
Now retired, the former entomologist [study of insects], said he volunteered as a hobby.
"It's only about a two kilometre dander along a beach but whenever you're doing it your eyes are focused and because I was an entomologist, I can spot really small things from a distance.
"It's good craic, the people who go out are dedicated," he continued.
"We do the easiest bit, it's the clean up after the survey. About two or three weeks later a team will go out from the local area and clean up the place."
The findings of the survey form part of a global database run by OSPAR, the international body responsible for protecting the north-eastern Atlantic.
It aims to get a picture of the scale of the problem and find solutions and, while the issue is very much global, Dr Humphreys said a "big cultural change" was also needed at home.
"Recent research showed 34% of people in Northern Ireland admit to littering: That's more than 600,000 people, so there's a lot of work to be done to change attitudes."
Worst offenders? Young men
That also leaves a large proportion of people who don't litter, and councils are seeing many groups of people meeting and going out to clean up.
One of the schemes run by Keep Northern Ireland Beautiful, Adopt a Spot, involves a group of volunteers selecting an area they will regularly visit and go to pick up litter.
"We had a new strategy in 2020 where we said we would try to reach 500 Adopt a Spot groups by 2025," he said.
"We have about 885 and growing today, just two years in."
That was being reflected across society in Northern Ireland, with volunteers acting as a deterrent to would-be litterers, "because they know that volunteers won't take kindly to seeing litter dropped in front of them".
But with the scale of the problem, "there's no one magic wand to wave," Dr Humphreys said.
"Many other necessary initiatives were already in motion, from increasing the visibility of bins that are already in place, to media campaigns targeting young males, the largest demographic of offenders when it comes to littering.
"Success will be underpinned by communities taking control of the quality of their local environment," he added.
"It'll be about people not tolerating littering in the area that they love and that is what we need to focus our efforts on.
"If we can get that right on litter, people will also be caring more about nature, biodiversity, the way they consume, how much they consume, repairing things rather than buying a new one when they break.
"This will bring cost savings as well as environmental benefits," said Dr Humphreys.
"And let's face it, without a healthy environment, people across the world are going to find out that it's problematic to live the way we do."