This is the official (in English) message from the Norwegian government:
The Government's decision is as follows:
HTML will be the primary format for publishing public information on the Internet.
PDF (PDF 1.4 and later or PDF/A ISO 19005-1) is obligatory when there is a wish to keep a document's original appearance.
ODF (ISO/IEC 26300) is to be used to publish documents to which the user should be able to make changes after downloading, e.g. public forms to be filled out by the user. This format is also made obligatory.