Proposals for a revamp of the Indonesian civil code could make sex outside marriage a crime.
Indonesian women could be jailed for live-in partnerships
The world's most populous Muslim nation is drafting regulations that could ban unmarried couples from having sex or living together.
The new laws would also make forcing a woman to perform oral sex a crime.
And homosexual acts by those under age 18 would be breaking the law.
Among the proposed punishments are:
"This is a response to the wishes of the people," Abdul Ghani Abdullah, Indonesia's director general of legislation, told the Associated Press news agency.
Couples found to be living together before marriage would face up to two years in prison.
A man breaking a promise to marry a woman pregnant by him could end up in prison for five years.
Acts of oral sex and sodomy would be punished by between three and 12 years in jail.
Homosexual sex could result in between one and seven years in prison.
However, the authorities will only investigate if someone lodges a complaint about another person's behaviour
"If the society chooses not to do anything and has no objection to any cohabitation for example, then it is not a crime," Mr Abdullah told Reuters.
The proposed laws are part of a major revamp of Indonesia's Criminal Code - a legacy of the country's Dutch colonial rulers.
The laws also propose to ban black magic and witchcraft.
The draft regulations will be submitted to parliament for debate and revision, Mr Abdullah said.
However, it could take years for them to become law, he added.