Support for Danish Prime Minister Lars Lokke Rasmussen's ruling Liberal Party has fallen to 16.6 percent from 19.5 percent at the June election, Borsen newspaper reported on Wednesday.

It was the lowest level since 1990 in opinion polls performed by the research institute Greens.

Liberal Party spokesman Jacob Jensen was quoted as saying the low support is due to "turbulent times" both economically and in relation to the migrant crisis that engulfed European politics in general.

Some 25 percent of respondents said they were satisfied with Rasmussen's handling of his job as prime minister, while 61 percent said they were not.

The opinion poll was conducted before the government decided to introduce border controls on Monday.