Jordanian MPs on Sunday amended a controversial electoral law, reserving more seats to party candidates, but failed to satisfy the Islamists, who have threatened to boycott early polls this year.
"The amendments increased seats that can be contested by party and coalition candidates from 17 to 27," prominent MP Khalil Attieh told AFP.
"This raises the number of parliamentary seats from 140 to 150, including 15 seats reserved for women candidates."
Following the approval of the law last month, the powerful Muslim Brotherhood described it as "provocative," saying they planned to boycott elections expected to be held by the end of this year.
"These changes are maybe good for kindergarten children. They are not good to start a real process of political reform," Zaki Bani Rsheid, deputy leader of the Brotherhood, told AFP after the amendments.
The Islamist movement will meet on Thursday to decide whether to go ahead with the election boycott, he added.
Jordan's King Abdullah II had ordered parliament to increase the seats for party candidates to "help develop political life in the country," urging the Islamists to take part in the elections.
The National Reform Front, headed by former premier and intelligence chief Ahmad Obeidat, also called for an election boycott, describing the law as "a real obstacle to reform."
"We call on all Jordanian people to boycott the elections," it said on Sunday.
Under the electoral law, voters can cast two ballots: one for individual candidates in their governorates and one for parties or coalitions.
According to the constitution, elections should be organised every four years, but Jordan held early polls in 2010 after the king dissolved parliament.
The Islamists boycotted those elections in protest at constituency boundaries, saying they over-represented loyalist rural areas at the expense of urban areas seen as Islamist strongholds.
They have repeatedly demanded sweeping changes that would lead to a parliamentary system in which the premier would be elected rather than named by the king.