A national survey shows housing sales in Canberra have started to slow down, in anticipation of this year's federal election.

The RP Data Rismark Home Value Index shows that nationally, over the 12 months to December, home prices fell by 0.4 per cent.

Canberra's average was a 0.3 per cent drop, with a more significant fall of around 1 per cent in the last three months.

Although, unit prices rose by 0.4 of a per cent for the period.

The median dwelling price is the second highest in the country at $517,000, behind Sydney which is still the most expensive city.

RP Data's senior research analyst Cameron Kusher says while values have remained strong in Canberra, the rate of sales has slowed down.

"I do think people are holding off their decision until the election," he said.

Mr Kusher says that has put the local market in a holding pattern.

"Canberra slightly outperformed the performance of the combined capital cities," he said.

"Overall it's not performing too badly, but if you have a look at sales activity it is fairly low at the moment.

"People simply aren't buying and selling houses to the same extent as they have in the past."