Unemployment has risen throughout 2009
The number of people on Jobseeker's Allowance (JSA) for more than a year has nearly doubled, the TUC has said.
Those claiming JSA for more than 12 months rose to 201,015 in November 2009, up from 103,930 in December 2008.
And 58 local authorities now have over 1,000 long-term claimants, compared with 19 last year.
The TUC is urging the government to extend its job guarantee for young people to everyone who has been unemployed for 18 months.
The TUC made the calculations using official claimant count data.
It wants to see the long-term unemployed entitled to a job paying at least the minimum wage for a minimum of six months.
Job Seeker's Allowance currently stands at £50.95 a week for 16-24 year olds, and £64.30 a week for those aged 25 and over.
The TUC is also calling for more help for those groups it says are at most risk of becoming the long-term unemployed.
These include people over 50, those who have spent a long time out of the labour market while caring for children or those with a history of unemployment.
TUC general secretary Brendan Barber says long-term joblessness is damaging.
"Every job loss is a human tragedy, but when people are out of work for over a year they risk being permanently scarred by joblessness," he said.
"The government should extend its job guarantee for young people to anyone out of work for 18 months to stop people getting mired in semi-permanent joblessness."
In his recent pre-Budget report, Alistair Darling announced that the government was extending its guarantee of a job or training to all young people who had been unemployed for six months.
Previously only those under 24 years old who had been jobless for 12 months were eligible.
The chancellor said he hoped to raise £550m from a 50% tax on bankers' bonuses to help ease unemployment.
In response to the TUC report, work and pensions minister Helen Goodman said long-term unemployment was an issue the government was trying to tackle.
"Action taken to help people back to work in the teeth of a deep global recession, backed by £5bn, has had a significant impact," she said.
"At 12 months unemployment everyone gets intensive support through the government's flagship flexible New Deal programme."
The number of people claiming unemployment benefit fell by 6,300 in November to 1.63 million, the first fall in claimants since February 2008.
However the number of people unemployed in the UK, using the government's preferred measure, now stands at 2.49 million.
These figures show that the number of people jobless for more than a year increased by 49,000 in the latest quarter to 620,000, the highest since 1997.
The number of people who say they are working part-time because they cannot find a full-time position rose by 34,000 in the quarter and now stands at over 1 million.