OpenDocument Format isn't just one format, it's a collection of formats. The one that corresponds to doc and docx is OpenDocument Text:

  site:gov.pt filetype:odt (1330 results)

Edit - For spreadsheets:

  site:gov.pt filetype:xls (2290 results)
  site:gov.pt filetype:xlsx (394 results)
  site:gov.pt filetype:ods (2 results)

Looks like they have a lot more work to do.