A total of 1,594 employers have been fined £400 for failing to comply with their workplace pension requirements since the start of automatic enrolment, the Pensions Regulator (TPR) has said.
The regulator noted a "sharp rise" in the number of times it needed to give "the additional nudge" to those who had not complied on time.
Its latest Compliance and enforcement bulletin showed that, of the total number of fines, 1,021 were issued in the last quarter of 2015.
Since auto-enrolment came into force in July 2012, TPR has issued 4,818 compliance notices, which instruct employers to remedy the breach of their duties. Of those, almost half (2,596) were issued between October and December 2015.
The regulator said the figures reflected the rise in the numbers of employers with automatic enrolment duties and that smaller employers were more likely to "leave things until the last minute".
TPR's executive director of automatic enrolment, Charles Counsell, said: "We have always expected to see a rise in the number of times we use our powers, as large numbers of small and micro-employers reach the date their duties come into effect. Compliance notices act as a warning and give employers a deadline to meet their duties and avoid a fine.
"Automatic enrolment is the law for all employers and we will use our powers where necessary to get them back on track."
TPR said around 12,000 small and micro employers became responsible for enrolling their staff into the scheme last summer, and more than 90% of them had done so without the regulator having to use its powers.
Counsell added: "It is very encouraging that more than 90% of the smallest employers have complied with the law, clearly highlighting that automatic enrolment is successful for all sizes of employer."
