The parliaments of Denmark, Finland and Sweden all have weekly Question Time when government ministers answer oral questions. In Sweden, the Prime Minister attends Question Time once per month. For Denmark and Finland, the regularity of Prime Minister attendance is not clear to me.
Hence the question is based on a false premise.
In OP's question is is stated:
In countries such as Denmark, Finland, and Sweden, the Parliament tend
to summon Ministers for questioning only when something serious has
occurred. These countries do not have the same culture as countries
with the Westminister System.
This seems to be a misunderstanding. Below I have quoted information from the websites of the parliaments of each of these three countries contradicting this description.
Here is an excerpt from an information page on the website of the Swedish Riksdag:
Question Time with the Government is held on Thursdays at 2 p.m. These
sessions are attended by four government ministers who come to answer
questions from members of the Riksdag. The ministers do not see the
questions in advance. Questions and answers have to be short and in
principle they should not exceed one minute each. Approximately once a
month the Prime Minister answers questions alone. This is known as the
Prime Minister's Question Time.
The right to address questions to the Government is one element of
parliamentary control. Members of the Riksdag can put both oral and
written questions to the Government. Thousands of questions are
usually asked during the course of a parliamentary year.
So question time with ministers is a weekly occurrence in Sweden, although the Prime Minister only attends once every month. Questions can be about any Government matter and when the Prime minister is not present, the other ministers will answer for the Government (to the best of their ability). Question time is not tied to specific events. This doesn't seem to be drastically different from the Westminster system.
Browsing the website of the Danish Folketing, I found this information:
Control through questioning
One method of exercising parliamentary control of the Government is to
put questions to Ministers. Collectively, Ministers are asked more
than 15,000 questions a year, primarily about current issues and
problems. To a certain extent, these questions may promote the
questioner's own opinion on a given issue. Parliamentary control can
thus be used to express political standpoints and to point out areas
Question Hour and Question Time
Individual MPs have various options for asking questions of Ministers.
One option is to submit questions in writing and ask for oral or
written replies. Written answers are forwarded continually whereas
oral answers are given briefly during the weekly Question Time in the
Chamber. MPs can also ask "impromptu questions", which means that
Ministers must answer questions they have not seen in advance. This
happens once a week during what is known as Question Hour. The purpose
of the Question Hour is to strengthen the political debate in the
And on the website of the Finnish Eduskunta if found this information:
MPs’ means to call the Government to account
Members can submit written questions to the minister responsible for a
particular matter. This is a request for the minister to provide
further information on the matter. The minister must reply to a
written question within 21 days after the question has been received
by the Prime Minister's Office.
Question time is held on Thursdays at the beginning of the plenary
session that starts at 4 pm. Here Members can present brief oral
questions to the appropriate ministers and hear their replies.
Ministers do not receive questions in advance, so question time is a
test of their command of timely issues in their administrative sector.
The Speaker decides the order in which Members may take the floor and
how long each topic may be discussed. Parliament does not vote on
matters during question time, which is televised by the Finnish
So it seems that the parliaments for all the countries you list have a weekly session where MPs can ask oral questions on any Government matter to ministers who have not seen the questions in advance. I did not find information specifically about the Prime Ministers' attendance in Denmark and Finland, but it seems MPs should be able to ask questions to any of the ministers, so I guess the Prime Minsters would need to attend somewhat regularly.