The Social Democratic leader "will call an election for parliament", news agency Ritzau reported.
Her office said she will make a statement at a press conference at 0900 GMT, without giving any further details.
Several other national media reported the same information.
The date of the election was unknown, Ritzau said, but Danish elections are typically held three weeks after the announcement is made.
A public opinion poll by Ritzau released on Monday showed the left-wing government and its allies in parliament credited with 45.6 per cent of voter sympathies, compared to 54.3 per cent for the opposition, which includes the anti-immigrant Danish People's Party (DPP).
