The unnamed firm must be sizeable as only firms with more than 2000 employees are so far required to enrol employees into a pension. But the rollout progresses by the month and this time next year firms with only 60 staff will hit their "staging date", with smaller firms staging over the next three years.
The Pensions Regulator said last month it had launched 89 investigations into possible non-compliance, and the first compliance notice (against an unnamed organisation) requires it to take specific remedial action.
Nigel Bolton, partner at law firm Irwin Mitchell which has an office in Glasgow, said: "Once again this shows the regulator isn't afraid to act. It reveals how challenging these laws are for larger well-resourced businesses and highlights what lies ahead for SMEs. It will no doubt be a wake-up call for many smaller companies.
"Our own research found that, although the majority of SMEs thought they were ready for auto-enrolment, in fact they hadn't considered many of the key issues. Hopefully this latest announcement will ensure they begin to take appropriate action."
The Department for Work and Pensions has reported 90% of workers enrolled into a pension scheme by their employer have stuck with it and only 9% have opted out.
Tom McPhail, head of pensions research at brokers Hargreaves Lansdown, said: "These early results are encouraging. However, there is still a great deal of work to be done. The largest employers were always likely to produce the best results so the real challenges still lie ahead."
Glynn Jones, a director at pensions advisers LEBC, said: "If the auto-enrolment project leads to a higher savings ratio, greater engagement in long-term financial planning and a better financially educated population, then we can celebrate accordingly in 2018.
"But if we are swapping savings into pensions from, for example Isas, and there is no upswing in people preparing properly for life beyond retirement, then the project will have failed."
Meanwhile the switch from final-salary schemes to defined contribution schemes in the private sector is costing workers up £1.27 billion a year in lost pension contributions, according to analysis from specialist Key Retirement Solutions.
It says employers are saving more than £1bn a year by moving workers from final-salary schemes to defined contribution and workers themselves are contributing £276 million less a year.
"The impact on a worker, on average earnings, of losing just five years of a defined benefit scheme can be as much as £2192 of pension income - which would require a private pension fund of around £38,000 to buy an equivalent annuity," KRS estimates.
Government figures show about 500,000 workers have been switched out of final salary - or defined benefit - pension schemes into defined contribution schemes in the past two years.
The average employer contribution into a final-salary scheme is 14.2% of an employee's salary while the average employee contribution is 4.9%. But in a defined contribution scheme the average employer contribution is 6.6% and the average employee contribution is 2.2%.
Dean Mirfin, group director at KRS, said: "Final-salary schemes are becoming increasingly rare in the private sector and it is entirely understandable that companies are finding it difficult to continue funding them. However, the impact of closure on scheme members is a major issue for retirement saving."
The Association of British Insurers last week launched a new pension calculator to help employers in selecting a workplace pension scheme for employees.
The initiative, backed by pensions minister Steve Webb, the National Association of Pension Funds and the Pensions Advisory Service among others, allows employers to input pension charges, including active member discounts and initial charges, to get a simple analysis of the impact the charges will have on their employees' retirement funds.
Mr McPhail, said: "Employers need all the help they can get in making good decision s on behalf of their employees. This tool will make it easier for them compare different pension schemes.
"Hopefully it will reduce the risk of employees being enrolled into unsuitable schemes. It is also important to note the other key factors determining pension pay outs, including how much is paid in, how long the employee saves for, where their money is invested and how they draw their retirement income."