ISTANBUL, July 30 (Reuters) - Hundreds of Turkish women posted pictures of themselves laughing on Twitter on Wednesday to protest against comments by Deputy Prime Minister Bulent Arinc who had urged women not to laugh in public to "protect moral values".

Melda Onur, a lawmaker from the main opposition party CHP said on Twitter Arinc's comments portrayed laughing as a dishonorable act and left women exposed to violence.

Opponents accuse Turkish Prime Minister Tayyip Erdogan's government of ruling in an increasingly authoritarian manner and meddling in people's private lives, which has long been a source of conflict between the country's secularists and Erdogan's conservative supporters.

Erdogan is running to become the first directly elected president of predominantly Muslim Turkey.

Arinc, one of the co-founders of Erdogan's AK Party, said this week at a celebration of Eid al-Fitr, marking the end of Ramadan: "The woman should have chastity ... She should not laugh in front of everyone and not be inviting in her behavior. She should protect her honor."

One women's organization said it would file a criminal complaint against the deputy PM.

Arinc's comments, in which he also criticized television soap operas for promoting decadence, also drew criticism from opposition presidential candidate Ekmeleddin Ihsanoglu who tweeted: "Our country needs our women to laugh and to hear everyone's joyful laughter more than ever."

(Reporting by Humeyra Pamuk; Editing by Janet Lawrence)