Just under a third of rents were raised compared to 28 per cent in November, according to agent trade body ARLA Propertymark.
The number of landlords selling their buy-to-let properties remained the same as November, according to ARLA with just four per branch – this was also the same level as a year previously.
The number of prospective tenants dipped in December month-on-month but was still around eight per cent higher year-on-year.
Regionally, the West Midlands had the highest number of new tenants registered per branch, while London had the second highest figure.
Mark Hayward, chief policy adviser at Propertymark, said: “The slight fall in prospective tenants and properties managed per branch during the month of December is consistent with the usual seasonal lull, and testament to the current steady rental market.
“Letting agents are continuing to support landlords and their tenants during these ongoing difficult times, and it is imperative that tenancies are maintained to keep the rent flowing. The continuity of the private rental sector is vital to the nation’s economic bounce back from the Covid-19 pandemic.”