The median weekly rent in Wellington jumped 6.7 per cent in December, hitting a new record of $480 per week.
Demand for rental properties in Wellington was "massive", Jeffries said, with the number of available properties dropping by 70 per cent.
"The capital is bearing the brunt of the rental shortage and January is likely to be even more extreme," he said.
"Since October, the median weekly rent in Wellington has increased $30, from $450 to $480 in December to match the record set in January 2017.
"We expect to see a new record price in January as the influx of university students heats the market even further."
A two-bedroom rental property in Wellington, listed for just 25 hours, received 55 applications, a prime example of the extent of demand.
Nationwide, the number of vacant rental properties has halved since December 2016 with the median weekly rent up 2.2 per cent and recorded as $460 per week.
"While it is common for us to see the median rent increase in December, it doesn't usually increase this much. The market is much tighter than usual and it is highly likely that tenants will be asked for record rents in January and February all over the country."