Microsoft's Office Open XML document format may have hit the first bumps on its road to becoming an International Standards Organisation (ISO) approved standard.

Nineteen countries, including some that have adopted the alternative ISO-approved OpenDocument format standard, have submitted comments and objections about Open XML to the ISO, according to a letter sent late last week by the Geneva-based international standards body.

Stacy Leistner, director of communication at the American National Standards Institute, which is helping the ISO manage the Open XML approval process, declined to say how many of the 19 submissions were "contradictions" – the ISO's term for serious objections to a proposed standard.

"It's up to each country to define what constitutes a contradiction to an existing ISO standard," Leistner said. "It could be anything from changing a comma here or there, or a more technical objection."

One official said his country's letter to the ISO leans toward the latter. "While Australia did not submit a formal contradiction, a number of issues were identified during our review that we believe warrant consideration," said Alistair Tegart, a program manager at Standards Australia, a Sydney-based standards body.

Open XML, the default file format in Office 2007, won certification in December as a standard by Ecma International, another Geneva-based standards group, after a year-long process shepherded by Microsoft.

The nations that submitted comments and objections to Open XML include more than half of the 30 countries in the ISO's IT committee, which will determine whether to bring Open XML's 6,000-page proposal to a general vote by ISO's 157 members.

"Of the 100-plus countries involved in this process, only 19 have made submissions," said Jason Matusow, senior director for intellectual property and interoperability at Microsoft. "We expect that some are either statements of support or simple statements that the ISO member has no comments at this stage."

Comments from the countries will be made public after 28 February. The ISO IT committee will then decide whether to put Open XML on a so-called fast track for a general vote within five months.