LEUVEN, Belgium (AFP) - European Union enlargement commissioner Guenter Verheugen said delays to a new penal code in Turkey were a "very worrying" development.

He said that doubts over the fate of a main plank in Turkey`s reform process could affect a European Commission appraisal of the country`s EU membership bid in a crucial report due out on October 6.

"It`s a very, let me say, worrying development that we see in Turkey and it will be much better to have the penal code adopted," he told reporters at an informal meeting of the incoming EU executive here.

"That might mean that there will be no adoption before October 6 and then, we have to take that into account," the German commissioner added.

The report into whether Turkey meets the exacting standards required of an EU membership hopeful will form the basis for a decision at the end of the year by EU leaders on whether to launch accession talks with Turkey.

Prime Minister Recep Tayyip Erdogan`s government has been pushing through far-reaching changes to Turkey`s 78-year-old penal code to bring it in line with European norms.

But the government unexpectedly withdrew its own bill Thursday in the face of pressure from radical MPs to introduce a controversial clause restoring adultery as a criminal offence in Turkey.

Verheugen`s spokesman Jean-Christophe Filori said criminalising adultery would "certainly cast doubt on the direction of Turkey`s reform efforts and would complicate Turkey`s European prospects".

"This would send the wrong signal ahead of the report on October 6. The outcome of this will be fully reflected in the report of October 6," he warned.

The European Commission is also concerned at reports by Turkish campaigners of torture and human rights violations, and has sent a fact-finding team to the country to look into the situation.

Filori said the unidentified senior official who is leading the team would only return to Brussels on Friday night so there had not been any feedback yet.

"We wait for the return of our people, and of course their findings will be reflected in our report on October 6," he said, while playing down speculation that the report`s release could be postponed.

"At present the deadline is October 6."

Prime Minister Erdogan convened the executive board of his Justice and Development Party (AKP) Friday to determine its next step a day after two articles of the bill were withdrawn in mid-debate.

But Erdogan also warned the EU against meddling in Turkey`s "internal affairs".

Next month`s eagerly awaited appraisal of Turkey`s EU bid will be one of the last major acts of the current Brussels executive before a new team takes over on November 1.

Verheugen, who is staying on in the new team, said the commission was as one on Turkey, undoubtedly the most important issue facing it today.

"My colleagues have every right to discuss one of the most important questions in the EU but on the issue that the commission has to decide, there is no split in the commission," he said.